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| 51 </head> | |
| 52 <body> | |
| 53 <div class="head"> | |
| 54 <p><a href="http://www.w3.org/"><img height=48 alt=W3C src="http://www.w3.org
/Icons/w3c_home" width=72></a> | |
| 55 | |
| 56 <h1 id="title">Selectors</h1> | |
| 57 | |
| 58 <h2>W3C Working Draft 15 December 2005</h2> | |
| 59 | |
| 60 <dl> | |
| 61 | |
| 62 <dt>This version: | |
| 63 | |
| 64 <dd><a href="http://www.w3.org/TR/2005/WD-css3-selectors-20051215"> | |
| 65 http://www.w3.org/TR/2005/WD-css3-selectors-20051215</a> | |
| 66 | |
| 67 <dt>Latest version: | |
| 68 | |
| 69 <dd><a href="http://www.w3.org/TR/css3-selectors"> | |
| 70 http://www.w3.org/TR/css3-selectors</a> | |
| 71 | |
| 72 <dt>Previous version: | |
| 73 | |
| 74 <dd><a href="http://www.w3.org/TR/2001/CR-css3-selectors-20011113"> | |
| 75 http://www.w3.org/TR/2001/CR-css3-selectors-20011113</a> | |
| 76 | |
| 77 <dt><a name=editors-list></a>Editors: | |
| 78 | |
| 79 <dd class="vcard"><span class="fn">Daniel Glazman</span> (Invited Expert)</d
d> | |
| 80 | |
| 81 <dd class="vcard"><a lang="tr" class="url fn" href="http://www.tantek.com/">
Tantek Çelik</a> (Invited Expert) | |
| 82 | |
| 83 <dd class="vcard"><a href="mailto:ian@hixie.ch" class="url fn">Ian Hickson</
a> (<span | |
| 84 class="company"><a href="http://www.google.com/">Google</a></span>) | |
| 85 | |
| 86 <dd class="vcard"><span class="fn">Peter Linss</span> (former editor, <span
class="company"><a | |
| 87 href="http://www.netscape.com/">Netscape/AOL</a></span>) | |
| 88 | |
| 89 <dd class="vcard"><span class="fn">John Williams</span> (former editor, <spa
n class="company"><a | |
| 90 href="http://www.quark.com/">Quark, Inc.</a></span>) | |
| 91 | |
| 92 </dl> | |
| 93 | |
| 94 <p class="copyright"><a | |
| 95 href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright"> | |
| 96 Copyright</a> © 2005 <a href="http://www.w3.org/"><abbr | |
| 97 title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> | |
| 98 (<a href="http://www.csail.mit.edu/"><abbr title="Massachusetts | |
| 99 Institute of Technology">MIT</abbr></a>, <a | |
| 100 href="http://www.ercim.org/"><acronym title="European Research | |
| 101 Consortium for Informatics and Mathematics">ERCIM</acronym></a>, <a | |
| 102 href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved. W3C | |
| 103 <a | |
| 104 href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liabili
ty</a>, | |
| 105 <a | |
| 106 href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark
</a>, | |
| 107 <a | |
| 108 href="http://www.w3.org/Consortium/Legal/copyright-documents">document | |
| 109 use</a> rules apply. | |
| 110 | |
| 111 <hr title="Separator for header"> | |
| 112 | |
| 113 </div> | |
| 114 | |
| 115 <h2><a name=abstract></a>Abstract</h2> | |
| 116 | |
| 117 <p><em>Selectors</em> are patterns that match against elements in a | |
| 118 tree. Selectors have been optimized for use with HTML and XML, and | |
| 119 are designed to be usable in performance-critical code.</p> | |
| 120 | |
| 121 <p><acronym title="Cascading Style Sheets">CSS</acronym> (Cascading | |
| 122 Style Sheets) is a language for describing the rendering of <acronym | |
| 123 title="Hypertext Markup Language">HTML</acronym> and <acronym | |
| 124 title="Extensible Markup Language">XML</acronym> documents on | |
| 125 screen, on paper, in speech, etc. CSS uses Selectors for binding | |
| 126 style properties to elements in the document. This document | |
| 127 describes extensions to the selectors defined in CSS level 2. These | |
| 128 extended selectors will be used by CSS level 3. | |
| 129 | |
| 130 <p>Selectors define the following function:</p> | |
| 131 | |
| 132 <pre>expression ∗ element → boolean</pre> | |
| 133 | |
| 134 <p>That is, given an element and a selector, this specification | |
| 135 defines whether that element matches the selector.</p> | |
| 136 | |
| 137 <p>These expressions can also be used, for instance, to select a set | |
| 138 of elements, or a single element from a set of elements, by | |
| 139 evaluating the expression across all the elements in a | |
| 140 subtree. <acronym title="Simple Tree Transformation | |
| 141 Sheets">STTS</acronym> (Simple Tree Transformation Sheets), a | |
| 142 language for transforming XML trees, uses this mechanism. <a href="#refsSTTS">
[STTS]</a></p> | |
| 143 | |
| 144 <h2><a name=status></a>Status of this document</h2> | |
| 145 | |
| 146 <p><em>This section describes the status of this document at the | |
| 147 time of its publication. Other documents may supersede this | |
| 148 document. A list of current W3C publications and the latest revision | |
| 149 of this technical report can be found in the <a | |
| 150 href="http://www.w3.org/TR/">W3C technical reports index at | |
| 151 http://www.w3.org/TR/.</a></em></p> | |
| 152 | |
| 153 <p>This document describes the selectors that already exist in <a | |
| 154 href="#refsCSS1"><abbr title="CSS level 1">CSS1</abbr></a> and <a | |
| 155 href="#refsCSS21"><abbr title="CSS level 2">CSS2</abbr></a>, and | |
| 156 also proposes new selectors for <abbr title="CSS level | |
| 157 3">CSS3</abbr> and other languages that may need them.</p> | |
| 158 | |
| 159 <p>The CSS Working Group doesn't expect that all implementations of | |
| 160 CSS3 will have to implement all selectors. Instead, there will | |
| 161 probably be a small number of variants of CSS3, called profiles. For | |
| 162 example, it may be that only a profile for interactive user agents | |
| 163 will include all of the selectors.</p> | |
| 164 | |
| 165 <p>This specification is a last call working draft for the the <a | |
| 166 href="http://www.w3.org/Style/CSS/members">CSS Working Group</a> | |
| 167 (<a href="/Style/">Style Activity</a>). This | |
| 168 document is a revision of the <a | |
| 169 href="http://www.w3.org/TR/2001/CR-css3-selectors-20011113/">Candidate | |
| 170 Recommendation dated 2001 November 13</a>, and has incorporated | |
| 171 implementation feedback received in the past few years. It is | |
| 172 expected that this last call will proceed straight to Proposed | |
| 173 Recommendation stage since it is believed that interoperability will | |
| 174 be demonstrable.</p> | |
| 175 | |
| 176 <p>All persons are encouraged to review and implement this | |
| 177 specification and return comments to the (<a | |
| 178 href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) | |
| 179 public mailing list <a | |
| 180 href="http://www.w3.org/Mail/Lists.html#www-style">www-style</a> | |
| 181 (see <a href="http://www.w3.org/Mail/Request">instructions</a>). W3C | |
| 182 Members can also send comments directly to the CSS Working | |
| 183 Group. | |
| 184 The deadline for comments is 14 January 2006.</p> | |
| 185 | |
| 186 <p>This is still a draft document and may be updated, replaced, or | |
| 187 obsoleted by other documents at any time. It is inappropriate to | |
| 188 cite a W3C Working Draft as other than "work in progress". | |
| 189 | |
| 190 <p>This document may be available in <a | |
| 191 href="http://www.w3.org/Style/css3-selectors-updates/translations">translation
</a>. | |
| 192 The English version of this specification is the only normative | |
| 193 version. | |
| 194 | |
| 195 <div class="subtoc"> | |
| 196 | |
| 197 <h2 id="test1"><a name=contents>Table of contents</a></h2> | |
| 198 | |
| 199 <ul class="toc"> | |
| 200 <li class="tocline2"><a href="#context">1. Introduction</a> | |
| 201 <ul> | |
| 202 <li><a href="#dependencies">1.1. Dependencies</a> </li> | |
| 203 <li><a href="#terminology">1.2. Terminology</a> </li> | |
| 204 <li><a href="#changesFromCSS2">1.3. Changes from CSS2</a> </li> | |
| 205 </ul> | |
| 206 <li class="tocline2"><a href="#selectors">2. Selectors</a> | |
| 207 <li class="tocline2"><a href="#casesens">3. Case sensitivity</a> | |
| 208 <li class="tocline2"><a href="#selector-syntax">4. Selector syntax</a> | |
| 209 <li class="tocline2"><a href="#grouping">5. Groups of selectors</a> | |
| 210 <li class="tocline2"><a href="#simple-selectors">6. Simple selectors</a> | |
| 211 <ul class="toc"> | |
| 212 <li class="tocline3"><a href="#type-selectors">6.1. Type selectors</a> | |
| 213 <ul class="toc"> | |
| 214 <li class="tocline4"><a href="#typenmsp">6.1.1. Type selectors and names
paces</a></li> | |
| 215 </ul> | |
| 216 <li class="tocline3"><a href="#universal-selector">6.2. Universal selector
</a> | |
| 217 <ul> | |
| 218 <li><a href="#univnmsp">6.2.1. Universal selector and namespaces</a></li
> | |
| 219 </ul> | |
| 220 <li class="tocline3"><a href="#attribute-selectors">6.3. Attribute selecto
rs</a> | |
| 221 <ul class="toc"> | |
| 222 <li class="tocline4"><a href="#attribute-representation">6.3.1. Represen
tation of attributes and attributes values</a> | |
| 223 <li><a href="#attribute-substrings">6.3.2. Substring matching attribute
selectors</a> | |
| 224 <li class="tocline4"><a href="#attrnmsp">6.3.3. Attribute selectors and
namespaces</a> | |
| 225 <li class="tocline4"><a href="#def-values">6.3.4. Default attribute valu
es in DTDs</a></li> | |
| 226 </ul> | |
| 227 <li class="tocline3"><a href="#class-html">6.4. Class selectors</a> | |
| 228 <li class="tocline3"><a href="#id-selectors">6.5. ID selectors</a> | |
| 229 <li class="tocline3"><a href="#pseudo-classes">6.6. Pseudo-classes</a> | |
| 230 <ul class="toc"> | |
| 231 <li class="tocline4"><a href="#dynamic-pseudos">6.6.1. Dynamic pseudo-cl
asses</a> | |
| 232 <li class="tocline4"><a href="#target-pseudo">6.6.2. The :target pseudo-
class</a> | |
| 233 <li class="tocline4"><a href="#lang-pseudo">6.6.3. The :lang() pseudo-cl
ass</a> | |
| 234 <li class="tocline4"><a href="#UIstates">6.6.4. UI element states pseudo
-classes</a> | |
| 235 <li class="tocline4"><a href="#structural-pseudos">6.6.5. Structural pse
udo-classes</a> | |
| 236 <ul> | |
| 237 <li><a href="#root-pseudo">:root pseudo-class</a> | |
| 238 <li><a href="#nth-child-pseudo">:nth-child() pseudo-class</a> | |
| 239 <li><a href="#nth-last-child-pseudo">:nth-last-child()</a> | |
| 240 <li><a href="#nth-of-type-pseudo">:nth-of-type() pseudo-class</a> | |
| 241 <li><a href="#nth-last-of-type-pseudo">:nth-last-of-type()</a> | |
| 242 <li><a href="#first-child-pseudo">:first-child pseudo-class</a> | |
| 243 <li><a href="#last-child-pseudo">:last-child pseudo-class</a> | |
| 244 <li><a href="#first-of-type-pseudo">:first-of-type pseudo-class</a> | |
| 245 <li><a href="#last-of-type-pseudo">:last-of-type pseudo-class</a> | |
| 246 <li><a href="#only-child-pseudo">:only-child pseudo-class</a> | |
| 247 <li><a href="#only-of-type-pseudo">:only-of-type pseudo-class</a> | |
| 248 <li><a href="#empty-pseudo">:empty pseudo-class</a></li> | |
| 249 </ul> | |
| 250 <li class="tocline4"><a href="#negation">6.6.7. The negation pseudo-clas
s</a></li> | |
| 251 </ul> | |
| 252 </li> | |
| 253 </ul> | |
| 254 <li><a href="#pseudo-elements">7. Pseudo-elements</a> | |
| 255 <ul> | |
| 256 <li><a href="#first-line">7.1. The ::first-line pseudo-element</a> | |
| 257 <li><a href="#first-letter">7.2. The ::first-letter pseudo-element</a> | |
| 258 <li><a href="#UIfragments">7.3. The ::selection pseudo-element</a> | |
| 259 <li><a href="#gen-content">7.4. The ::before and ::after pseudo-elements</
a></li> | |
| 260 </ul> | |
| 261 <li class="tocline2"><a href="#combinators">8. Combinators</a> | |
| 262 <ul class="toc"> | |
| 263 <li class="tocline3"><a href="#descendant-combinators">8.1. Descendant com
binators</a> | |
| 264 <li class="tocline3"><a href="#child-combinators">8.2. Child combinators</
a> | |
| 265 <li class="tocline3"><a href="#sibling-combinators">8.3. Sibling combinato
rs</a> | |
| 266 <ul class="toc"> | |
| 267 <li class="tocline4"><a href="#adjacent-sibling-combinators">8.3.1. Adja
cent sibling combinator</a> | |
| 268 <li class="tocline4"><a href="#general-sibling-combinators">8.3.2. Gener
al sibling combinator</a></li> | |
| 269 </ul> | |
| 270 </li> | |
| 271 </ul> | |
| 272 <li class="tocline2"><a href="#specificity">9. Calculating a selector's spec
ificity</a> | |
| 273 <li class="tocline2"><a href="#w3cselgrammar">10. The grammar of Selectors</
a> | |
| 274 <ul class="toc"> | |
| 275 <li class="tocline3"><a href="#grammar">10.1. Grammar</a> | |
| 276 <li class="tocline3"><a href="#lex">10.2. Lexical scanner</a></li> | |
| 277 </ul> | |
| 278 <li class="tocline2"><a href="#downlevel">11. Namespaces and down-level clie
nts</a> | |
| 279 <li class="tocline2"><a href="#profiling">12. Profiles</a> | |
| 280 <li><a href="#Conformance">13. Conformance and requirements</a> | |
| 281 <li><a href="#Tests">14. Tests</a> | |
| 282 <li><a href="#ACKS">15. Acknowledgements</a> | |
| 283 <li class="tocline2"><a href="#references">16. References</a> | |
| 284 </ul> | |
| 285 | |
| 286 </div> | |
| 287 | |
| 288 <h2><a name=context>1. Introduction</a></h2> | |
| 289 | |
| 290 <h3><a name=dependencies></a>1.1. Dependencies</h3> | |
| 291 | |
| 292 <p>Some features of this specification are specific to CSS, or have | |
| 293 particular limitations or rules specific to CSS. In this | |
| 294 specification, these have been described in terms of CSS2.1. <a | |
| 295 href="#refsCSS21">[CSS21]</a></p> | |
| 296 | |
| 297 <h3><a name=terminology></a>1.2. Terminology</h3> | |
| 298 | |
| 299 <p>All of the text of this specification is normative except | |
| 300 examples, notes, and sections explicitly marked as | |
| 301 non-normative.</p> | |
| 302 | |
| 303 <h3><a name=changesFromCSS2></a>1.3. Changes from CSS2</h3> | |
| 304 | |
| 305 <p><em>This section is non-normative.</em></p> | |
| 306 | |
| 307 <p>The main differences between the selectors in CSS2 and those in | |
| 308 Selectors are: | |
| 309 | |
| 310 <ul> | |
| 311 | |
| 312 <li>the list of basic definitions (selector, group of selectors, | |
| 313 simple selector, etc.) has been changed; in particular, what was | |
| 314 referred to in CSS2 as a simple selector is now called a sequence | |
| 315 of simple selectors, and the term "simple selector" is now used for | |
| 316 the components of this sequence</li> | |
| 317 | |
| 318 <li>an optional namespace component is now allowed in type element | |
| 319 selectors, the universal selector and attribute selectors</li> | |
| 320 | |
| 321 <li>a <a href="#general-sibling-combinators">new combinator</a> has been intr
oduced</li> | |
| 322 | |
| 323 <li>new simple selectors including substring matching attribute | |
| 324 selectors, and new pseudo-classes</li> | |
| 325 | |
| 326 <li>new pseudo-elements, and introduction of the "::" convention | |
| 327 for pseudo-elements</li> | |
| 328 | |
| 329 <li>the grammar has been rewritten</li> | |
| 330 | |
| 331 <li>profiles to be added to specifications integrating Selectors | |
| 332 and defining the set of selectors which is actually supported by | |
| 333 each specification</li> | |
| 334 | |
| 335 <li>Selectors are now a CSS3 Module and an independent | |
| 336 specification; other specifications can now refer to this document | |
| 337 independently of CSS</li> | |
| 338 | |
| 339 <li>the specification now has its own test suite</li> | |
| 340 | |
| 341 </ul> | |
| 342 | |
| 343 <h2><a name=selectors></a>2. Selectors</h2> | |
| 344 | |
| 345 <p><em>This section is non-normative, as it merely summarizes the | |
| 346 following sections.</em></p> | |
| 347 | |
| 348 <p>A Selector represents a structure. This structure can be used as a | |
| 349 condition (e.g. in a CSS rule) that determines which elements a | |
| 350 selector matches in the document tree, or as a flat description of the | |
| 351 HTML or XML fragment corresponding to that structure.</p> | |
| 352 | |
| 353 <p>Selectors may range from simple element names to rich contextual | |
| 354 representations.</p> | |
| 355 | |
| 356 <p>The following table summarizes the Selector syntax:</p> | |
| 357 | |
| 358 <table class="selectorsReview"> | |
| 359 <thead> | |
| 360 <tr> | |
| 361 <th class="pattern">Pattern</th> | |
| 362 <th class="meaning">Meaning</th> | |
| 363 <th class="described">Described in section</th> | |
| 364 <th class="origin">First defined in CSS level</th></tr> | |
| 365 <tbody> | |
| 366 <tr> | |
| 367 <td class="pattern">*</td> | |
| 368 <td class="meaning">any element</td> | |
| 369 <td class="described"><a | |
| 370 href="#universal-selector">Universal | |
| 371 selector</a></td> | |
| 372 <td class="origin">2</td></tr> | |
| 373 <tr> | |
| 374 <td class="pattern">E</td> | |
| 375 <td class="meaning">an element of type E</td> | |
| 376 <td class="described"><a | |
| 377 href="#type-selectors">Type selector</a></td> | |
| 378 <td class="origin">1</td></tr> | |
| 379 <tr> | |
| 380 <td class="pattern">E[foo]</td> | |
| 381 <td class="meaning">an E element with a "foo" attribute</td> | |
| 382 <td class="described"><a | |
| 383 href="#attribute-selectors">Attribute | |
| 384 selectors</a></td> | |
| 385 <td class="origin">2</td></tr> | |
| 386 <tr> | |
| 387 <td class="pattern">E[foo="bar"]</td> | |
| 388 <td class="meaning">an E element whose "foo" attribute value is exactly | |
| 389 equal to "bar"</td> | |
| 390 <td class="described"><a | |
| 391 href="#attribute-selectors">Attribute | |
| 392 selectors</a></td> | |
| 393 <td class="origin">2</td></tr> | |
| 394 <tr> | |
| 395 <td class="pattern">E[foo~="bar"]</td> | |
| 396 <td class="meaning">an E element whose "foo" attribute value is a list of | |
| 397 space-separated values, one of which is exactly equal to "bar"</td> | |
| 398 <td class="described"><a | |
| 399 href="#attribute-selectors">Attribute | |
| 400 selectors</a></td> | |
| 401 <td class="origin">2</td></tr> | |
| 402 <tr> | |
| 403 <td class="pattern">E[foo^="bar"]</td> | |
| 404 <td class="meaning">an E element whose "foo" attribute value begins exactly | |
| 405 with the string "bar"</td> | |
| 406 <td class="described"><a | |
| 407 href="#attribute-selectors">Attribute | |
| 408 selectors</a></td> | |
| 409 <td class="origin">3</td></tr> | |
| 410 <tr> | |
| 411 <td class="pattern">E[foo$="bar"]</td> | |
| 412 <td class="meaning">an E element whose "foo" attribute value ends exactly | |
| 413 with the string "bar"</td> | |
| 414 <td class="described"><a | |
| 415 href="#attribute-selectors">Attribute | |
| 416 selectors</a></td> | |
| 417 <td class="origin">3</td></tr> | |
| 418 <tr> | |
| 419 <td class="pattern">E[foo*="bar"]</td> | |
| 420 <td class="meaning">an E element whose "foo" attribute value contains the | |
| 421 substring "bar"</td> | |
| 422 <td class="described"><a | |
| 423 href="#attribute-selectors">Attribute | |
| 424 selectors</a></td> | |
| 425 <td class="origin">3</td></tr> | |
| 426 <tr> | |
| 427 <td class="pattern">E[hreflang|="en"]</td> | |
| 428 <td class="meaning">an E element whose "hreflang" attribute has a hyphen-sep
arated | |
| 429 list of values beginning (from the left) with "en"</td> | |
| 430 <td class="described"><a | |
| 431 href="#attribute-selectors">Attribute | |
| 432 selectors</a></td> | |
| 433 <td class="origin">2</td></tr> | |
| 434 <tr> | |
| 435 <td class="pattern">E:root</td> | |
| 436 <td class="meaning">an E element, root of the document</td> | |
| 437 <td class="described"><a | |
| 438 href="#structural-pseudos">Structural | |
| 439 pseudo-classes</a></td> | |
| 440 <td class="origin">3</td></tr> | |
| 441 <tr> | |
| 442 <td class="pattern">E:nth-child(n)</td> | |
| 443 <td class="meaning">an E element, the n-th child of its parent</td> | |
| 444 <td class="described"><a | |
| 445 href="#structural-pseudos">Structural | |
| 446 pseudo-classes</a></td> | |
| 447 <td class="origin">3</td></tr> | |
| 448 <tr> | |
| 449 <td class="pattern">E:nth-last-child(n)</td> | |
| 450 <td class="meaning">an E element, the n-th child of its parent, counting | |
| 451 from the last one</td> | |
| 452 <td class="described"><a | |
| 453 href="#structural-pseudos">Structural | |
| 454 pseudo-classes</a></td> | |
| 455 <td class="origin">3</td></tr> | |
| 456 <tr> | |
| 457 <td class="pattern">E:nth-of-type(n)</td> | |
| 458 <td class="meaning">an E element, the n-th sibling of its type</td> | |
| 459 <td class="described"><a | |
| 460 href="#structural-pseudos">Structural | |
| 461 pseudo-classes</a></td> | |
| 462 <td class="origin">3</td></tr> | |
| 463 <tr> | |
| 464 <td class="pattern">E:nth-last-of-type(n)</td> | |
| 465 <td class="meaning">an E element, the n-th sibling of its type, counting | |
| 466 from the last one</td> | |
| 467 <td class="described"><a | |
| 468 href="#structural-pseudos">Structural | |
| 469 pseudo-classes</a></td> | |
| 470 <td class="origin">3</td></tr> | |
| 471 <tr> | |
| 472 <td class="pattern">E:first-child</td> | |
| 473 <td class="meaning">an E element, first child of its parent</td> | |
| 474 <td class="described"><a | |
| 475 href="#structural-pseudos">Structural | |
| 476 pseudo-classes</a></td> | |
| 477 <td class="origin">2</td></tr> | |
| 478 <tr> | |
| 479 <td class="pattern">E:last-child</td> | |
| 480 <td class="meaning">an E element, last child of its parent</td> | |
| 481 <td class="described"><a | |
| 482 href="#structural-pseudos">Structural | |
| 483 pseudo-classes</a></td> | |
| 484 <td class="origin">3</td></tr> | |
| 485 <tr> | |
| 486 <td class="pattern">E:first-of-type</td> | |
| 487 <td class="meaning">an E element, first sibling of its type</td> | |
| 488 <td class="described"><a | |
| 489 href="#structural-pseudos">Structural | |
| 490 pseudo-classes</a></td> | |
| 491 <td class="origin">3</td></tr> | |
| 492 <tr> | |
| 493 <td class="pattern">E:last-of-type</td> | |
| 494 <td class="meaning">an E element, last sibling of its type</td> | |
| 495 <td class="described"><a | |
| 496 href="#structural-pseudos">Structural | |
| 497 pseudo-classes</a></td> | |
| 498 <td class="origin">3</td></tr> | |
| 499 <tr> | |
| 500 <td class="pattern">E:only-child</td> | |
| 501 <td class="meaning">an E element, only child of its parent</td> | |
| 502 <td class="described"><a | |
| 503 href="#structural-pseudos">Structural | |
| 504 pseudo-classes</a></td> | |
| 505 <td class="origin">3</td></tr> | |
| 506 <tr> | |
| 507 <td class="pattern">E:only-of-type</td> | |
| 508 <td class="meaning">an E element, only sibling of its type</td> | |
| 509 <td class="described"><a | |
| 510 href="#structural-pseudos">Structural | |
| 511 pseudo-classes</a></td> | |
| 512 <td class="origin">3</td></tr> | |
| 513 <tr> | |
| 514 <td class="pattern">E:empty</td> | |
| 515 <td class="meaning">an E element that has no children (including text | |
| 516 nodes)</td> | |
| 517 <td class="described"><a | |
| 518 href="#structural-pseudos">Structural | |
| 519 pseudo-classes</a></td> | |
| 520 <td class="origin">3</td></tr> | |
| 521 <tr> | |
| 522 <td class="pattern">E:link<br>E:visited</td> | |
| 523 <td class="meaning">an E element being the source anchor of a hyperlink of | |
| 524 which the target is not yet visited (:link) or already visited | |
| 525 (:visited)</td> | |
| 526 <td class="described"><a | |
| 527 href="#link">The link | |
| 528 pseudo-classes</a></td> | |
| 529 <td class="origin">1</td></tr> | |
| 530 <tr> | |
| 531 <td class="pattern">E:active<br>E:hover<br>E:focus</td> | |
| 532 <td class="meaning">an E element during certain user actions</td> | |
| 533 <td class="described"><a | |
| 534 href="#useraction-pseudos">The user | |
| 535 action pseudo-classes</a></td> | |
| 536 <td class="origin">1 and 2</td></tr> | |
| 537 <tr> | |
| 538 <td class="pattern">E:target</td> | |
| 539 <td class="meaning">an E element being the target of the referring URI</td> | |
| 540 <td class="described"><a | |
| 541 href="#target-pseudo">The target | |
| 542 pseudo-class</a></td> | |
| 543 <td class="origin">3</td></tr> | |
| 544 <tr> | |
| 545 <td class="pattern">E:lang(fr)</td> | |
| 546 <td class="meaning">an element of type E in language "fr" (the document | |
| 547 language specifies how language is determined)</td> | |
| 548 <td class="described"><a | |
| 549 href="#lang-pseudo">The :lang() | |
| 550 pseudo-class</a></td> | |
| 551 <td class="origin">2</td></tr> | |
| 552 <tr> | |
| 553 <td class="pattern">E:enabled<br>E:disabled</td> | |
| 554 <td class="meaning">a user interface element E which is enabled or | |
| 555 disabled</td> | |
| 556 <td class="described"><a | |
| 557 href="#UIstates">The UI element states | |
| 558 pseudo-classes</a></td> | |
| 559 <td class="origin">3</td></tr> | |
| 560 <tr> | |
| 561 <td class="pattern">E:checked<!--<br>E:indeterminate--></td> | |
| 562 <td class="meaning">a user interface element E which is checked<!-- or in an | |
| 563 indeterminate state--> (for instance a radio-button or checkbox)</td> | |
| 564 <td class="described"><a | |
| 565 href="#UIstates">The UI element states | |
| 566 pseudo-classes</a></td> | |
| 567 <td class="origin">3</td></tr> | |
| 568 <tr> | |
| 569 <td class="pattern">E::first-line</td> | |
| 570 <td class="meaning">the first formatted line of an E element</td> | |
| 571 <td class="described"><a | |
| 572 href="#first-line">The ::first-line | |
| 573 pseudo-element</a></td> | |
| 574 <td class="origin">1</td></tr> | |
| 575 <tr> | |
| 576 <td class="pattern">E::first-letter</td> | |
| 577 <td class="meaning">the first formatted letter of an E element</td> | |
| 578 <td class="described"><a | |
| 579 href="#first-letter">The ::first-letter | |
| 580 pseudo-element</a></td> | |
| 581 <td class="origin">1</td></tr> | |
| 582 <tr> | |
| 583 <td class="pattern">E::selection</td> | |
| 584 <td class="meaning">the portion of an E element that is currently | |
| 585 selected/highlighted by the user</td> | |
| 586 <td class="described"><a | |
| 587 href="#UIfragments">The UI element | |
| 588 fragments pseudo-elements</a></td> | |
| 589 <td class="origin">3</td></tr> | |
| 590 <tr> | |
| 591 <td class="pattern">E::before</td> | |
| 592 <td class="meaning">generated content before an E element</td> | |
| 593 <td class="described"><a | |
| 594 href="#gen-content">The ::before | |
| 595 pseudo-element</a></td> | |
| 596 <td class="origin">2</td></tr> | |
| 597 <tr> | |
| 598 <td class="pattern">E::after</td> | |
| 599 <td class="meaning">generated content after an E element</td> | |
| 600 <td class="described"><a | |
| 601 href="#gen-content">The ::after | |
| 602 pseudo-element</a></td> | |
| 603 <td class="origin">2</td></tr> | |
| 604 <tr> | |
| 605 <td class="pattern">E.warning</td> | |
| 606 <td class="meaning">an E element whose class is | |
| 607 "warning" (the document language specifies how class is determined).</td> | |
| 608 <td class="described"><a | |
| 609 href="#class-html">Class | |
| 610 selectors</a></td> | |
| 611 <td class="origin">1</td></tr> | |
| 612 <tr> | |
| 613 <td class="pattern">E#myid</td> | |
| 614 <td class="meaning">an E element with ID equal to "myid".</td> | |
| 615 <td class="described"><a | |
| 616 href="#id-selectors">ID | |
| 617 selectors</a></td> | |
| 618 <td class="origin">1</td></tr> | |
| 619 <tr> | |
| 620 <td class="pattern">E:not(s)</td> | |
| 621 <td class="meaning">an E element that does not match simple selector s</td> | |
| 622 <td class="described"><a | |
| 623 href="#negation">Negation | |
| 624 pseudo-class</a></td> | |
| 625 <td class="origin">3</td></tr> | |
| 626 <tr> | |
| 627 <td class="pattern">E F</td> | |
| 628 <td class="meaning">an F element descendant of an E element</td> | |
| 629 <td class="described"><a | |
| 630 href="#descendant-combinators">Descendant | |
| 631 combinator</a></td> | |
| 632 <td class="origin">1</td></tr> | |
| 633 <tr> | |
| 634 <td class="pattern">E > F</td> | |
| 635 <td class="meaning">an F element child of an E element</td> | |
| 636 <td class="described"><a | |
| 637 href="#child-combinators">Child | |
| 638 combinator</a></td> | |
| 639 <td class="origin">2</td></tr> | |
| 640 <tr> | |
| 641 <td class="pattern">E + F</td> | |
| 642 <td class="meaning">an F element immediately preceded by an E element</td> | |
| 643 <td class="described"><a | |
| 644 href="#adjacent-sibling-combinators">Adjacent sibling combinator</a></td> | |
| 645 <td class="origin">2</td></tr> | |
| 646 <tr> | |
| 647 <td class="pattern">E ~ F</td> | |
| 648 <td class="meaning">an F element preceded by an E element</td> | |
| 649 <td class="described"><a | |
| 650 href="#general-sibling-combinators">General sibling combinator</a></td> | |
| 651 <td class="origin">3</td></tr></tbody></table> | |
| 652 | |
| 653 <p>The meaning of each selector is derived from the table above by | |
| 654 prepending "matches" to the contents of each cell in the "Meaning" | |
| 655 column.</p> | |
| 656 | |
| 657 <h2><a name=casesens>3. Case sensitivity</a></h2> | |
| 658 | |
| 659 <p>The case sensitivity of document language element names, attribute | |
| 660 names, and attribute values in selectors depends on the document | |
| 661 language. For example, in HTML, element names are case-insensitive, | |
| 662 but in XML, they are case-sensitive.</p> | |
| 663 | |
| 664 <h2><a name=selector-syntax>4. Selector syntax</a></h2> | |
| 665 | |
| 666 <p>A <dfn><a name=selector>selector</a></dfn> is a chain of one | |
| 667 or more <a href="#sequence">sequences of simple selectors</a> | |
| 668 separated by <a href="#combinators">combinators</a>.</p> | |
| 669 | |
| 670 <p>A <dfn><a name=sequence>sequence of simple selectors</a></dfn> | |
| 671 is a chain of <a href="#simple-selectors-dfn">simple selectors</a> | |
| 672 that are not separated by a <a href="#combinators">combinator</a>. It | |
| 673 always begins with a <a href="#type-selectors">type selector</a> or a | |
| 674 <a href="#universal-selector">universal selector</a>. No other type | |
| 675 selector or universal selector is allowed in the sequence.</p> | |
| 676 | |
| 677 <p>A <dfn><a name=simple-selectors-dfn></a><a | |
| 678 href="#simple-selectors">simple selector</a></dfn> is either a <a | |
| 679 href="#type-selectors">type selector</a>, <a | |
| 680 href="#universal-selector">universal selector</a>, <a | |
| 681 href="#attribute-selectors">attribute selector</a>, <a | |
| 682 href="#class-html">class selector</a>, <a | |
| 683 href="#id-selectors">ID selector</a>, <a | |
| 684 href="#content-selectors">content selector</a>, or <a | |
| 685 href="#pseudo-classes">pseudo-class</a>. One <a | |
| 686 href="#pseudo-elements">pseudo-element</a> may be appended to the last | |
| 687 sequence of simple selectors.</p> | |
| 688 | |
| 689 <p><dfn>Combinators</dfn> are: white space, "greater-than | |
| 690 sign" (U+003E, <code>></code>), "plus sign" (U+002B, | |
| 691 <code>+</code>) and "tilde" (U+007E, <code>~</code>). White | |
| 692 space may appear between a combinator and the simple selectors around | |
| 693 it. <a name=whitespace></a>Only the characters "space" (U+0020), "tab" | |
| 694 (U+0009), "line feed" (U+000A), "carriage return" (U+000D), and "form | |
| 695 feed" (U+000C) can occur in white space. Other space-like characters, | |
| 696 such as "em-space" (U+2003) and "ideographic space" (U+3000), are | |
| 697 never part of white space.</p> | |
| 698 | |
| 699 <p>The elements of a document tree that are represented by a selector | |
| 700 are the <dfn><a name=subject></a>subjects of the selector</dfn>. A | |
| 701 selector consisting of a single sequence of simple selectors | |
| 702 represents any element satisfying its requirements. Prepending another | |
| 703 sequence of simple selectors and a combinator to a sequence imposes | |
| 704 additional matching constraints, so the subjects of a selector are | |
| 705 always a subset of the elements represented by the last sequence of | |
| 706 simple selectors.</p> | |
| 707 | |
| 708 <p>An empty selector, containing no sequence of simple selectors and | |
| 709 no pseudo-element, is an <a href="#Conformance">invalid | |
| 710 selector</a>.</p> | |
| 711 | |
| 712 <h2><a name=grouping>5. Groups of selectors</a></h2> | |
| 713 | |
| 714 <p>When several selectors share the same declarations, they may be | |
| 715 grouped into a comma-separated list. (A comma is U+002C.)</p> | |
| 716 | |
| 717 <div class="example"> | |
| 718 <p>CSS examples:</p> | |
| 719 <p>In this example, we condense three rules with identical | |
| 720 declarations into one. Thus,</p> | |
| 721 <pre>h1 { font-family: sans-serif } | |
| 722 h2 { font-family: sans-serif } | |
| 723 h3 { font-family: sans-serif }</pre> | |
| 724 <p>is equivalent to:</p> | |
| 725 <pre>h1, h2, h3 { font-family: sans-serif }</pre> | |
| 726 </div> | |
| 727 | |
| 728 <p><strong>Warning</strong>: the equivalence is true in this example | |
| 729 because all the selectors are valid selectors. If just one of these | |
| 730 selectors were invalid, the entire group of selectors would be | |
| 731 invalid. This would invalidate the rule for all three heading | |
| 732 elements, whereas in the former case only one of the three individual | |
| 733 heading rules would be invalidated.</p> | |
| 734 | |
| 735 | |
| 736 <h2><a name=simple-selectors>6. Simple selectors</a></h2> | |
| 737 | |
| 738 <h3><a name=type-selectors>6.1. Type selector</a></h3> | |
| 739 | |
| 740 <p>A <dfn>type selector</dfn> is the name of a document language | |
| 741 element type. A type selector represents an instance of the element | |
| 742 type in the document tree.</p> | |
| 743 | |
| 744 <div class="example"> | |
| 745 <p>Example:</p> | |
| 746 <p>The following selector represents an <code>h1</code> element in the document
tree:</p> | |
| 747 <pre>h1</pre> | |
| 748 </div> | |
| 749 | |
| 750 | |
| 751 <h4><a name=typenmsp>6.1.1. Type selectors and namespaces</a></h4> | |
| 752 | |
| 753 <p>Type selectors allow an optional namespace (<a | |
| 754 href="#refsXMLNAMES">[XMLNAMES]</a>) component. A namespace prefix | |
| 755 that has been previously declared may be prepended to the element name | |
| 756 separated by the namespace separator "vertical bar" | |
| 757 (U+007C, <code>|</code>).</p> | |
| 758 | |
| 759 <p>The namespace component may be left empty to indicate that the | |
| 760 selector is only to represent elements with no declared namespace.</p> | |
| 761 | |
| 762 <p>An asterisk may be used for the namespace prefix, indicating that | |
| 763 the selector represents elements in any namespace (including elements | |
| 764 with no namespace).</p> | |
| 765 | |
| 766 <p>Element type selectors that have no namespace component (no | |
| 767 namespace separator), represent elements without regard to the | |
| 768 element's namespace (equivalent to "<code>*|</code>") unless a default | |
| 769 namespace has been declared. If a default namespace has been declared, | |
| 770 the selector will represent only elements in the default | |
| 771 namespace.</p> | |
| 772 | |
| 773 <p>A type selector containing a namespace prefix that has not been | |
| 774 previously declared is an <a href="#Conformance">invalid</a> selector. | |
| 775 The mechanism for declaring a namespace prefix is left up to the | |
| 776 language implementing Selectors. In CSS, such a mechanism is defined | |
| 777 in the General Syntax module.</p> | |
| 778 | |
| 779 <p>In a namespace-aware client, element type selectors will only match | |
| 780 against the <a | |
| 781 href="http://www.w3.org/TR/REC-xml-names/#NT-LocalPart">local part</a> | |
| 782 of the element's <a | |
| 783 href="http://www.w3.org/TR/REC-xml-names/#ns-qualnames">qualified | |
| 784 name</a>. See <a href="#downlevel">below</a> for notes about matching | |
| 785 behaviors in down-level clients.</p> | |
| 786 | |
| 787 <p>In summary:</p> | |
| 788 | |
| 789 <dl> | |
| 790 <dt><code>ns|E</code></dt> | |
| 791 <dd>elements with name E in namespace ns</dd> | |
| 792 <dt><code>*|E</code></dt> | |
| 793 <dd>elements with name E in any namespace, including those without any | |
| 794 declared namespace</dd> | |
| 795 <dt><code>|E</code></dt> | |
| 796 <dd>elements with name E without any declared namespace</dd> | |
| 797 <dt><code>E</code></dt> | |
| 798 <dd>if no default namespace has been specified, this is equivalent to *|E. | |
| 799 Otherwise it is equivalent to ns|E where ns is the default namespace.</dd> | |
| 800 </dl> | |
| 801 | |
| 802 <div class="example"> | |
| 803 <p>CSS examples:</p> | |
| 804 | |
| 805 <pre>@namespace foo url(http://www.example.com); | |
| 806 foo|h1 { color: blue } | |
| 807 foo|* { color: yellow } | |
| 808 |h1 { color: red } | |
| 809 *|h1 { color: green } | |
| 810 h1 { color: green }</pre> | |
| 811 | |
| 812 <p>The first rule will match only <code>h1</code> elements in the | |
| 813 "http://www.example.com" namespace.</p> | |
| 814 | |
| 815 <p>The second rule will match all elements in the | |
| 816 "http://www.example.com" namespace.</p> | |
| 817 | |
| 818 <p>The third rule will match only <code>h1</code> elements without | |
| 819 any declared namespace.</p> | |
| 820 | |
| 821 <p>The fourth rule will match <code>h1</code> elements in any | |
| 822 namespace (including those without any declared namespace).</p> | |
| 823 | |
| 824 <p>The last rule is equivalent to the fourth rule because no default | |
| 825 namespace has been defined.</p> | |
| 826 | |
| 827 </div> | |
| 828 | |
| 829 <h3><a name=universal-selector>6.2. Universal selector</a> </h3> | |
| 830 | |
| 831 <p>The <dfn>universal selector</dfn>, written "asterisk" | |
| 832 (<code>*</code>), represents the qualified name of any element | |
| 833 type. It represents any single element in the document tree in any | |
| 834 namespace (including those without any declared namespace) if no | |
| 835 default namespace has been specified. If a default namespace has been | |
| 836 specified, see <a href="#univnmsp">Universal selector and | |
| 837 Namespaces</a> below.</p> | |
| 838 | |
| 839 <p>If the universal selector is not the only component of a sequence | |
| 840 of simple selectors, the <code>*</code> may be omitted.</p> | |
| 841 | |
| 842 <div class="example"> | |
| 843 <p>Examples:</p> | |
| 844 <ul> | |
| 845 <li><code>*[hreflang|=en]</code> and <code>[hreflang|=en]</code> are equivalen
t,</li> | |
| 846 <li><code>*.warning</code> and <code>.warning</code> are equivalent,</li> | |
| 847 <li><code>*#myid</code> and <code>#myid</code> are equivalent.</li> | |
| 848 </ul> | |
| 849 </div> | |
| 850 | |
| 851 <p class="note"><strong>Note:</strong> it is recommended that the | |
| 852 <code>*</code>, representing the universal selector, not be | |
| 853 omitted.</p> | |
| 854 | |
| 855 <h4><a name=univnmsp>6.2.1. Universal selector and namespaces</a></h4> | |
| 856 | |
| 857 <p>The universal selector allows an optional namespace component. It | |
| 858 is used as follows:</p> | |
| 859 | |
| 860 <dl> | |
| 861 <dt><code>ns|*</code></dt> | |
| 862 <dd>all elements in namespace ns</dd> | |
| 863 <dt><code>*|*</code></dt> | |
| 864 <dd>all elements</dd> | |
| 865 <dt><code>|*</code></dt> | |
| 866 <dd>all elements without any declared namespace</dd> | |
| 867 <dt><code>*</code></dt> | |
| 868 <dd>if no default namespace has been specified, this is equivalent to *|*. | |
| 869 Otherwise it is equivalent to ns|* where ns is the default namespace.</dd> | |
| 870 </dl> | |
| 871 | |
| 872 <p>A universal selector containing a namespace prefix that has not | |
| 873 been previously declared is an <a href="#Conformance">invalid</a> | |
| 874 selector. The mechanism for declaring a namespace prefix is left up | |
| 875 to the language implementing Selectors. In CSS, such a mechanism is | |
| 876 defined in the General Syntax module.</p> | |
| 877 | |
| 878 | |
| 879 <h3><a name=attribute-selectors>6.3. Attribute selectors</a></h3> | |
| 880 | |
| 881 <p>Selectors allow the representation of an element's attributes. When | |
| 882 a selector is used as an expression to match against an element, | |
| 883 attribute selectors must be considered to match an element if that | |
| 884 element has an attribute that matches the attribute represented by the | |
| 885 attribute selector.</p> | |
| 886 | |
| 887 <h4><a name=attribute-representation>6.3.1. Attribute presence and values | |
| 888 selectors</a></h4> | |
| 889 | |
| 890 <p>CSS2 introduced four attribute selectors:</p> | |
| 891 | |
| 892 <dl> | |
| 893 <dt><code>[att]</code> | |
| 894 <dd>Represents an element with the <code>att</code> attribute, whatever the va
lue of | |
| 895 the attribute.</dd> | |
| 896 <dt><code>[att=val]</code></dt> | |
| 897 <dd>Represents an element with the <code>att</code> attribute whose value is e
xactly | |
| 898 "val".</dd> | |
| 899 <dt><code>[att~=val]</code></dt> | |
| 900 <dd>Represents an element with the <code>att</code> attribute whose value is a
<a | |
| 901 href="#whitespace">whitespace</a>-separated list of words, one of | |
| 902 which is exactly "val". If "val" contains whitespace, it will never | |
| 903 represent anything (since the words are <em>separated</em> by | |
| 904 spaces).</dd> | |
| 905 <dt><code>[att|=val]</code> | |
| 906 <dd>Represents an element with the <code>att</code> attribute, its value eithe
r | |
| 907 being exactly "val" or beginning with "val" immediately followed by | |
| 908 "-" (U+002D). This is primarily intended to allow language subcode | |
| 909 matches (e.g., the <code>hreflang</code> attribute on the | |
| 910 <code>link</code> element in HTML) as described in RFC 3066 (<a | |
| 911 href="#refsRFC3066">[RFC3066]</a>). For <code>lang</code> (or | |
| 912 <code>xml:lang</code>) language subcode matching, please see <a | |
| 913 href="#lang-pseudo">the <code>:lang</code> pseudo-class</a>.</dd> | |
| 914 </dl> | |
| 915 | |
| 916 <p>Attribute values must be identifiers or strings. The | |
| 917 case-sensitivity of attribute names and values in selectors depends on | |
| 918 the document language.</p> | |
| 919 | |
| 920 <div class="example"> | |
| 921 | |
| 922 <p>Examples:</p> | |
| 923 | |
| 924 <p>The following attribute selector represents an <code>h1</code> | |
| 925 element that carries the <code>title</code> attribute, whatever its | |
| 926 value:</p> | |
| 927 | |
| 928 <pre>h1[title]</pre> | |
| 929 | |
| 930 <p>In the following example, the selector represents a | |
| 931 <code>span</code> element whose <code>class</code> attribute has | |
| 932 exactly the value "example":</p> | |
| 933 | |
| 934 <pre>span[class="example"]</pre> | |
| 935 | |
| 936 <p>Multiple attribute selectors can be used to represent several | |
| 937 attributes of an element, or several conditions on the same | |
| 938 attribute. Here, the selector represents a <code>span</code> element | |
| 939 whose <code>hello</code> attribute has exactly the value "Cleveland" | |
| 940 and whose <code>goodbye</code> attribute has exactly the value | |
| 941 "Columbus":</p> | |
| 942 | |
| 943 <pre>span[hello="Cleveland"][goodbye="Columbus"]</pre> | |
| 944 | |
| 945 <p>The following selectors illustrate the differences between "=" | |
| 946 and "~=". The first selector will represent, for example, the value | |
| 947 "copyright copyleft copyeditor" on a <code>rel</code> attribute. The | |
| 948 second selector will only represent an <code>a</code> element with | |
| 949 an <code>href</code> attribute having the exact value | |
| 950 "http://www.w3.org/".</p> | |
| 951 | |
| 952 <pre>a[rel~="copyright"] | |
| 953 a[href="http://www.w3.org/"]</pre> | |
| 954 | |
| 955 <p>The following selector represents a <code>link</code> element | |
| 956 whose <code>hreflang</code> attribute is exactly "fr".</p> | |
| 957 | |
| 958 <pre>link[hreflang=fr]</pre> | |
| 959 | |
| 960 <p>The following selector represents a <code>link</code> element for | |
| 961 which the values of the <code>hreflang</code> attribute begins with | |
| 962 "en", including "en", "en-US", and "en-cockney":</p> | |
| 963 | |
| 964 <pre>link[hreflang|="en"]</pre> | |
| 965 | |
| 966 <p>Similarly, the following selectors represents a | |
| 967 <code>DIALOGUE</code> element whenever it has one of two different | |
| 968 values for an attribute <code>character</code>:</p> | |
| 969 | |
| 970 <pre>DIALOGUE[character=romeo] | |
| 971 DIALOGUE[character=juliet]</pre> | |
| 972 | |
| 973 </div> | |
| 974 | |
| 975 <h4><a name=attribute-substrings></a>6.3.2. Substring matching attribute | |
| 976 selectors</h4> | |
| 977 | |
| 978 <p>Three additional attribute selectors are provided for matching | |
| 979 substrings in the value of an attribute:</p> | |
| 980 | |
| 981 <dl> | |
| 982 <dt><code>[att^=val]</code></dt> | |
| 983 <dd>Represents an element with the <code>att</code> attribute whose value begi
ns | |
| 984 with the prefix "val".</dd> | |
| 985 <dt><code>[att$=val]</code> | |
| 986 <dd>Represents an element with the <code>att</code> attribute whose value ends
with | |
| 987 the suffix "val".</dd> | |
| 988 <dt><code>[att*=val]</code> | |
| 989 <dd>Represents an element with the <code>att</code> attribute whose value cont
ains | |
| 990 at least one instance of the substring "val".</dd> | |
| 991 </dl> | |
| 992 | |
| 993 <p>Attribute values must be identifiers or strings. The | |
| 994 case-sensitivity of attribute names in selectors depends on the | |
| 995 document language.</p> | |
| 996 | |
| 997 <div class="example"> | |
| 998 <p>Examples:</p> | |
| 999 <p>The following selector represents an HTML <code>object</code>, referencing a
n | |
| 1000 image:</p> | |
| 1001 <pre>object[type^="image/"]</pre> | |
| 1002 <p>The following selector represents an HTML anchor <code>a</code> with an | |
| 1003 <code>href</code> attribute whose value ends with ".html".</p> | |
| 1004 <pre>a[href$=".html"]</pre> | |
| 1005 <p>The following selector represents an HTML paragraph with a <code>title</code
> | |
| 1006 attribute whose value contains the substring "hello"</p> | |
| 1007 <pre>p[title*="hello"]</pre> | |
| 1008 </div> | |
| 1009 | |
| 1010 <h4><a name=attrnmsp>6.3.3. Attribute selectors and namespaces</a></h4> | |
| 1011 | |
| 1012 <p>Attribute selectors allow an optional namespace component to the | |
| 1013 attribute name. A namespace prefix that has been previously declared | |
| 1014 may be prepended to the attribute name separated by the namespace | |
| 1015 separator "vertical bar" (<code>|</code>). In keeping with | |
| 1016 the Namespaces in the XML recommendation, default namespaces do not | |
| 1017 apply to attributes, therefore attribute selectors without a namespace | |
| 1018 component apply only to attributes that have no declared namespace | |
| 1019 (equivalent to "<code>|attr</code>"). An asterisk may be used for the | |
| 1020 namespace prefix indicating that the selector is to match all | |
| 1021 attribute names without regard to the attribute's namespace. | |
| 1022 | |
| 1023 <p>An attribute selector with an attribute name containing a namespace | |
| 1024 prefix that has not been previously declared is an <a | |
| 1025 href="#Conformance">invalid</a> selector. The mechanism for declaring | |
| 1026 a namespace prefix is left up to the language implementing Selectors. | |
| 1027 In CSS, such a mechanism is defined in the General Syntax module. | |
| 1028 | |
| 1029 <div class="example"> | |
| 1030 <p>CSS examples:</p> | |
| 1031 <pre>@namespace foo "http://www.example.com"; | |
| 1032 [foo|att=val] { color: blue } | |
| 1033 [*|att] { color: yellow } | |
| 1034 [|att] { color: green } | |
| 1035 [att] { color: green }</pre> | |
| 1036 | |
| 1037 <p>The first rule will match only elements with the attribute | |
| 1038 <code>att</code> in the "http://www.example.com" namespace with the | |
| 1039 value "val".</p> | |
| 1040 | |
| 1041 <p>The second rule will match only elements with the attribute | |
| 1042 <code>att</code> regardless of the namespace of the attribute | |
| 1043 (including no declared namespace).</p> | |
| 1044 | |
| 1045 <p>The last two rules are equivalent and will match only elements | |
| 1046 with the attribute <code>att</code> where the attribute is not | |
| 1047 declared to be in a namespace.</p> | |
| 1048 | |
| 1049 </div> | |
| 1050 | |
| 1051 <h4><a name=def-values>6.3.4. Default attribute values in DTDs</a></h4> | |
| 1052 | |
| 1053 <p>Attribute selectors represent explicitly set attribute values in | |
| 1054 the document tree. Default attribute values may be defined in a DTD or | |
| 1055 elsewhere, but cannot always be selected by attribute | |
| 1056 selectors. Selectors should be designed so that they work even if the | |
| 1057 default values are not included in the document tree.</p> | |
| 1058 | |
| 1059 <p>More precisely, a UA is <em>not</em> required to read an "external | |
| 1060 subset" of the DTD but <em>is</em> required to look for default | |
| 1061 attribute values in the document's "internal subset." (See <a | |
| 1062 href="#refsXML10">[XML10]</a> for definitions of these subsets.)</p> | |
| 1063 | |
| 1064 <p>A UA that recognizes an XML namespace <a | |
| 1065 href="#refsXMLNAMES">[XMLNAMES]</a> is not required to use its | |
| 1066 knowledge of that namespace to treat default attribute values as if | |
| 1067 they were present in the document. (For example, an XHTML UA is not | |
| 1068 required to use its built-in knowledge of the XHTML DTD.)</p> | |
| 1069 | |
| 1070 <p class="note"><strong>Note:</strong> Typically, implementations | |
| 1071 choose to ignore external subsets.</p> | |
| 1072 | |
| 1073 <div class="example"> | |
| 1074 <p>Example:</p> | |
| 1075 | |
| 1076 <p>Consider an element EXAMPLE with an attribute "notation" that has a | |
| 1077 default value of "decimal". The DTD fragment might be</p> | |
| 1078 | |
| 1079 <pre class="dtd-example"><!ATTLIST EXAMPLE notation (decimal,octal) "decimal"
></pre> | |
| 1080 | |
| 1081 <p>If the style sheet contains the rules</p> | |
| 1082 | |
| 1083 <pre>EXAMPLE[notation=decimal] { /*... default property settings ...*/ } | |
| 1084 EXAMPLE[notation=octal] { /*... other settings...*/ }</pre> | |
| 1085 | |
| 1086 <p>the first rule will not match elements whose "notation" attribute | |
| 1087 is set by default, i.e. not set explicitly. To catch all cases, the | |
| 1088 attribute selector for the default value must be dropped:</p> | |
| 1089 | |
| 1090 <pre>EXAMPLE { /*... default property settings ...*/ } | |
| 1091 EXAMPLE[notation=octal] { /*... other settings...*/ }</pre> | |
| 1092 | |
| 1093 <p>Here, because the selector <code>EXAMPLE[notation=octal]</code> is | |
| 1094 more specific than the tag | |
| 1095 selector alone, the style declarations in the second rule will override | |
| 1096 those in the first for elements that have a "notation" attribute value | |
| 1097 of "octal". Care has to be taken that all property declarations that | |
| 1098 are to apply only to the default case are overridden in the non-default | |
| 1099 cases' style rules.</p> | |
| 1100 | |
| 1101 </div> | |
| 1102 | |
| 1103 <h3><a name=class-html>6.4. Class selectors</a></h3> | |
| 1104 | |
| 1105 <p>Working with HTML, authors may use the period (U+002E, | |
| 1106 <code>.</code>) notation as an alternative to the <code>~=</code> | |
| 1107 notation when representing the <code>class</code> attribute. Thus, for | |
| 1108 HTML, <code>div.value</code> and <code>div[class~=value]</code> have | |
| 1109 the same meaning. The attribute value must immediately follow the | |
| 1110 "period" (<code>.</code>).</p> | |
| 1111 | |
| 1112 <p>UAs may apply selectors using the period (.) notation in XML | |
| 1113 documents if the UA has namespace-specific knowledge that allows it to | |
| 1114 determine which attribute is the "class" attribute for the | |
| 1115 respective namespace. One such example of namespace-specific knowledge | |
| 1116 is the prose in the specification for a particular namespace (e.g. SVG | |
| 1117 1.0 <a href="#refsSVG">[SVG]</a> describes the <a | |
| 1118 href="http://www.w3.org/TR/2001/PR-SVG-20010719/styling.html#ClassAttribute">SVG | |
| 1119 "class" attribute</a> and how a UA should interpret it, and | |
| 1120 similarly MathML 1.01 <a href="#refsMATH">[MATH]</a> describes the <a | |
| 1121 href="http://www.w3.org/1999/07/REC-MathML-19990707/chapter2.html#sec2.3.4">Math
ML | |
| 1122 "class" attribute</a>.)</p> | |
| 1123 | |
| 1124 <div class="example"> | |
| 1125 <p>CSS examples:</p> | |
| 1126 | |
| 1127 <p>We can assign style information to all elements with | |
| 1128 <code>class~="pastoral"</code> as follows:</p> | |
| 1129 | |
| 1130 <pre>*.pastoral { color: green } /* all elements with class~=pastoral */</pre
> | |
| 1131 | |
| 1132 <p>or just</p> | |
| 1133 | |
| 1134 <pre>.pastoral { color: green } /* all elements with class~=pastoral */</pre> | |
| 1135 | |
| 1136 <p>The following assigns style only to H1 elements with | |
| 1137 <code>class~="pastoral"</code>:</p> | |
| 1138 | |
| 1139 <pre>H1.pastoral { color: green } /* H1 elements with class~=pastoral */</pre
> | |
| 1140 | |
| 1141 <p>Given these rules, the first H1 instance below would not have | |
| 1142 green text, while the second would:</p> | |
| 1143 | |
| 1144 <pre><H1>Not green</H1> | |
| 1145 <H1 class="pastoral">Very green</H1></pre> | |
| 1146 | |
| 1147 </div> | |
| 1148 | |
| 1149 <p>To represent a subset of "class" values, each value must be preceded | |
| 1150 by a ".", in any order.</P> | |
| 1151 | |
| 1152 <div class="example"> | |
| 1153 | |
| 1154 <p>CSS example:</p> | |
| 1155 | |
| 1156 <p>The following rule matches any P element whose "class" attribute | |
| 1157 has been assigned a list of <a | |
| 1158 href="#whitespace">whitespace</a>-separated values that includes | |
| 1159 "pastoral" and "marine":</p> | |
| 1160 | |
| 1161 <pre>p.pastoral.marine { color: green }</pre> | |
| 1162 | |
| 1163 <p>This rule matches when <code>class="pastoral blue aqua | |
| 1164 marine"</code> but does not match for <code>class="pastoral | |
| 1165 blue"</code>.</p> | |
| 1166 | |
| 1167 </div> | |
| 1168 | |
| 1169 <p class="note"><strong>Note:</strong> Because CSS gives considerable | |
| 1170 power to the "class" attribute, authors could conceivably design their | |
| 1171 own "document language" based on elements with almost no associated | |
| 1172 presentation (such as DIV and SPAN in HTML) and assigning style | |
| 1173 information through the "class" attribute. Authors should avoid this | |
| 1174 practice since the structural elements of a document language often | |
| 1175 have recognized and accepted meanings and author-defined classes may | |
| 1176 not.</p> | |
| 1177 | |
| 1178 <p class="note"><strong>Note:</strong> If an element has multiple | |
| 1179 class attributes, their values must be concatenated with spaces | |
| 1180 between the values before searching for the class. As of this time the | |
| 1181 working group is not aware of any manner in which this situation can | |
| 1182 be reached, however, so this behavior is explicitly non-normative in | |
| 1183 this specification.</p> | |
| 1184 | |
| 1185 <h3><a name=id-selectors>6.5. ID selectors</a></h3> | |
| 1186 | |
| 1187 <p>Document languages may contain attributes that are declared to be | |
| 1188 of type ID. What makes attributes of type ID special is that no two | |
| 1189 such attributes can have the same value in a document, regardless of | |
| 1190 the type of the elements that carry them; whatever the document | |
| 1191 language, an ID typed attribute can be used to uniquely identify its | |
| 1192 element. In HTML all ID attributes are named "id"; XML applications | |
| 1193 may name ID attributes differently, but the same restriction | |
| 1194 applies.</p> | |
| 1195 | |
| 1196 <p>An ID-typed attribute of a document language allows authors to | |
| 1197 assign an identifier to one element instance in the document tree. W3C | |
| 1198 ID selectors represent an element instance based on its identifier. An | |
| 1199 ID selector contains a "number sign" (U+0023, | |
| 1200 <code>#</code>) immediately followed by the ID value, which must be an | |
| 1201 identifier.</p> | |
| 1202 | |
| 1203 <p>Selectors does not specify how a UA knows the ID-typed attribute of | |
| 1204 an element. The UA may, e.g., read a document's DTD, have the | |
| 1205 information hard-coded or ask the user. | |
| 1206 | |
| 1207 <div class="example"> | |
| 1208 <p>Examples:</p> | |
| 1209 <p>The following ID selector represents an <code>h1</code> element | |
| 1210 whose ID-typed attribute has the value "chapter1":</p> | |
| 1211 <pre>h1#chapter1</pre> | |
| 1212 <p>The following ID selector represents any element whose ID-typed | |
| 1213 attribute has the value "chapter1":</p> | |
| 1214 <pre>#chapter1</pre> | |
| 1215 <p>The following selector represents any element whose ID-typed | |
| 1216 attribute has the value "z98y".</p> | |
| 1217 <pre>*#z98y</pre> | |
| 1218 </div> | |
| 1219 | |
| 1220 <p class="note"><strong>Note.</strong> In XML 1.0 <a | |
| 1221 href="#refsXML10">[XML10]</a>, the information about which attribute | |
| 1222 contains an element's IDs is contained in a DTD or a schema. When | |
| 1223 parsing XML, UAs do not always read the DTD, and thus may not know | |
| 1224 what the ID of an element is (though a UA may have namespace-specific | |
| 1225 knowledge that allows it to determine which attribute is the ID | |
| 1226 attribute for that namespace). If a style sheet designer knows or | |
| 1227 suspects that a UA may not know what the ID of an element is, he | |
| 1228 should use normal attribute selectors instead: | |
| 1229 <code>[name=p371]</code> instead of <code>#p371</code>. Elements in | |
| 1230 XML 1.0 documents without a DTD do not have IDs at all.</p> | |
| 1231 | |
| 1232 <p>If an element has multiple ID attributes, all of them must be | |
| 1233 treated as IDs for that element for the purposes of the ID | |
| 1234 selector. Such a situation could be reached using mixtures of xml:id, | |
| 1235 DOM3 Core, XML DTDs, and namespace-specific knowledge.</p> | |
| 1236 | |
| 1237 <h3><a name=pseudo-classes>6.6. Pseudo-classes</a></h3> | |
| 1238 | |
| 1239 <p>The pseudo-class concept is introduced to permit selection based on | |
| 1240 information that lies outside of the document tree or that cannot be | |
| 1241 expressed using the other simple selectors.</p> | |
| 1242 | |
| 1243 <p>A pseudo-class always consists of a "colon" | |
| 1244 (<code>:</code>) followed by the name of the pseudo-class and | |
| 1245 optionally by a value between parentheses.</p> | |
| 1246 | |
| 1247 <p>Pseudo-classes are allowed in all sequences of simple selectors | |
| 1248 contained in a selector. Pseudo-classes are allowed anywhere in | |
| 1249 sequences of simple selectors, after the leading type selector or | |
| 1250 universal selector (possibly omitted). Pseudo-class names are | |
| 1251 case-insensitive. Some pseudo-classes are mutually exclusive, while | |
| 1252 others can be applied simultaneously to the same | |
| 1253 element. Pseudo-classes may be dynamic, in the sense that an element | |
| 1254 may acquire or lose a pseudo-class while a user interacts with the | |
| 1255 document.</p> | |
| 1256 | |
| 1257 | |
| 1258 <h4><a name=dynamic-pseudos>6.6.1. Dynamic pseudo-classes</a></h4> | |
| 1259 | |
| 1260 <p>Dynamic pseudo-classes classify elements on characteristics other | |
| 1261 than their name, attributes, or content, in principle characteristics | |
| 1262 that cannot be deduced from the document tree.</p> | |
| 1263 | |
| 1264 <p>Dynamic pseudo-classes do not appear in the document source or | |
| 1265 document tree.</p> | |
| 1266 | |
| 1267 | |
| 1268 <h5>The <a name=link>link pseudo-classes: :link and :visited</a></h5> | |
| 1269 | |
| 1270 <p>User agents commonly display unvisited links differently from | |
| 1271 previously visited ones. Selectors | |
| 1272 provides the pseudo-classes <code>:link</code> and | |
| 1273 <code>:visited</code> to distinguish them:</p> | |
| 1274 | |
| 1275 <ul> | |
| 1276 <li>The <code>:link</code> pseudo-class applies to links that have | |
| 1277 not yet been visited.</li> | |
| 1278 <li>The <code>:visited</code> pseudo-class applies once the link has | |
| 1279 been visited by the user. </li> | |
| 1280 </ul> | |
| 1281 | |
| 1282 <p>After some amount of time, user agents may choose to return a | |
| 1283 visited link to the (unvisited) ':link' state.</p> | |
| 1284 | |
| 1285 <p>The two states are mutually exclusive.</p> | |
| 1286 | |
| 1287 <div class="example"> | |
| 1288 | |
| 1289 <p>Example:</p> | |
| 1290 | |
| 1291 <p>The following selector represents links carrying class | |
| 1292 <code>external</code> and already visited:</p> | |
| 1293 | |
| 1294 <pre>a.external:visited</pre> | |
| 1295 | |
| 1296 </div> | |
| 1297 | |
| 1298 <p class="note"><strong>Note:</strong> It is possible for style sheet | |
| 1299 authors to abuse the :link and :visited pseudo-classes to determine | |
| 1300 which sites a user has visited without the user's consent. | |
| 1301 | |
| 1302 <p>UAs may therefore treat all links as unvisited links, or implement | |
| 1303 other measures to preserve the user's privacy while rendering visited | |
| 1304 and unvisited links differently.</p> | |
| 1305 | |
| 1306 <h5>The <a name=useraction-pseudos>user action pseudo-classes | |
| 1307 :hover, :active, and :focus</a></h5> | |
| 1308 | |
| 1309 <p>Interactive user agents sometimes change the rendering in response | |
| 1310 to user actions. Selectors provides | |
| 1311 three pseudo-classes for the selection of an element the user is | |
| 1312 acting on.</p> | |
| 1313 | |
| 1314 <ul> | |
| 1315 | |
| 1316 <li>The <code>:hover</code> pseudo-class applies while the user | |
| 1317 designates an element with a pointing device, but does not activate | |
| 1318 it. For example, a visual user agent could apply this pseudo-class | |
| 1319 when the cursor (mouse pointer) hovers over a box generated by the | |
| 1320 element. User agents not that do not support <a | |
| 1321 href="http://www.w3.org/TR/REC-CSS2/media.html#interactive-media-group">intera
ctive | |
| 1322 media</a> do not have to support this pseudo-class. Some conforming | |
| 1323 user agents that support <a | |
| 1324 href="http://www.w3.org/TR/REC-CSS2/media.html#interactive-media-group">intera
ctive | |
| 1325 media</a> may not be able to support this pseudo-class (e.g., a pen | |
| 1326 device that does not detect hovering).</li> | |
| 1327 | |
| 1328 <li>The <code>:active</code> pseudo-class applies while an element | |
| 1329 is being activated by the user. For example, between the times the | |
| 1330 user presses the mouse button and releases it.</li> | |
| 1331 | |
| 1332 <li>The <code>:focus</code> pseudo-class applies while an element | |
| 1333 has the focus (accepts keyboard or mouse events, or other forms of | |
| 1334 input). </li> | |
| 1335 | |
| 1336 </ul> | |
| 1337 | |
| 1338 <p>There may be document language or implementation specific limits on | |
| 1339 which elements can become <code>:active</code> or acquire | |
| 1340 <code>:focus</code>.</p> | |
| 1341 | |
| 1342 <p>These pseudo-classes are not mutually exclusive. An element may | |
| 1343 match several pseudo-classes at the same time.</p> | |
| 1344 | |
| 1345 <p>Selectors doesn't define if the parent of an element that is | |
| 1346 ':active' or ':hover' is also in that state.</p> | |
| 1347 | |
| 1348 <div class="example"> | |
| 1349 <p>Examples:</p> | |
| 1350 <pre>a:link /* unvisited links */ | |
| 1351 a:visited /* visited links */ | |
| 1352 a:hover /* user hovers */ | |
| 1353 a:active /* active links */</pre> | |
| 1354 <p>An example of combining dynamic pseudo-classes:</p> | |
| 1355 <pre>a:focus | |
| 1356 a:focus:hover</pre> | |
| 1357 <p>The last selector matches <code>a</code> elements that are in | |
| 1358 the pseudo-class :focus and in the pseudo-class :hover.</p> | |
| 1359 </div> | |
| 1360 | |
| 1361 <p class="note"><strong>Note:</strong> An element can be both ':visited' | |
| 1362 and ':active' (or ':link' and ':active').</p> | |
| 1363 | |
| 1364 <h4><a name=target-pseudo>6.6.2. The target pseudo-class :target</a></h4> | |
| 1365 | |
| 1366 <p>Some URIs refer to a location within a resource. This kind of URI | |
| 1367 ends with a "number sign" (#) followed by an anchor | |
| 1368 identifier (called the fragment identifier).</p> | |
| 1369 | |
| 1370 <p>URIs with fragment identifiers link to a certain element within the | |
| 1371 document, known as the target element. For instance, here is a URI | |
| 1372 pointing to an anchor named <code>section_2</code> in an HTML | |
| 1373 document:</p> | |
| 1374 | |
| 1375 <pre>http://example.com/html/top.html#section_2</pre> | |
| 1376 | |
| 1377 <p>A target element can be represented by the <code>:target</code> | |
| 1378 pseudo-class. If the document's URI has no fragment identifier, then | |
| 1379 the document has no target element.</p> | |
| 1380 | |
| 1381 <div class="example"> | |
| 1382 <p>Example:</p> | |
| 1383 <pre>p.note:target</pre> | |
| 1384 <p>This selector represents a <code>p</code> element of class | |
| 1385 <code>note</code> that is the target element of the referring | |
| 1386 URI.</p> | |
| 1387 </div> | |
| 1388 | |
| 1389 <div class="example"> | |
| 1390 <p>CSS example:</p> | |
| 1391 <p>Here, the <code>:target</code> pseudo-class is used to make the | |
| 1392 target element red and place an image before it, if there is one:</p> | |
| 1393 <pre>*:target { color : red } | |
| 1394 *:target::before { content : url(target.png) }</pre> | |
| 1395 </div> | |
| 1396 | |
| 1397 <h4><a name=lang-pseudo>6.6.3. The language pseudo-class :lang</a></h4> | |
| 1398 | |
| 1399 <p>If the document language specifies how the human language of an | |
| 1400 element is determined, it is possible to write selectors that | |
| 1401 represent an element based on its language. For example, in HTML <a | |
| 1402 href="#refsHTML4">[HTML4]</a>, the language is determined by a | |
| 1403 combination of the <code>lang</code> attribute, the <code>meta</code> | |
| 1404 element, and possibly by information from the protocol (such as HTTP | |
| 1405 headers). XML uses an attribute called <code>xml:lang</code>, and | |
| 1406 there may be other document language-specific methods for determining | |
| 1407 the language.</p> | |
| 1408 | |
| 1409 <p>The pseudo-class <code>:lang(C)</code> represents an element that | |
| 1410 is in language C. Whether an element is represented by a | |
| 1411 <code>:lang()</code> selector is based solely on the identifier C | |
| 1412 being either equal to, or a hyphen-separated substring of, the | |
| 1413 element's language value, in the same way as if performed by the <a | |
| 1414 href="#attribute-representation">'|='</a> operator in attribute | |
| 1415 selectors. The identifier C does not have to be a valid language | |
| 1416 name.</p> | |
| 1417 | |
| 1418 <p>C must not be empty. (If it is, the selector is invalid.)</p> | |
| 1419 | |
| 1420 <p class="note"><strong>Note:</strong> It is recommended that | |
| 1421 documents and protocols indicate language using codes from RFC 3066 <a | |
| 1422 href="#refsRFC3066">[RFC3066]</a> or its successor, and by means of | |
| 1423 "xml:lang" attributes in the case of XML-based documents <a | |
| 1424 href="#refsXML10">[XML10]</a>. See <a | |
| 1425 href="http://www.w3.org/International/questions/qa-lang-2or3.html"> | |
| 1426 "FAQ: Two-letter or three-letter language codes."</a></p> | |
| 1427 | |
| 1428 <div class="example"> | |
| 1429 <p>Examples:</p> | |
| 1430 <p>The two following selectors represent an HTML document that is in | |
| 1431 Belgian, French, or German. The two next selectors represent | |
| 1432 <code>q</code> quotations in an arbitrary element in Belgian, French, | |
| 1433 or German.</p> | |
| 1434 <pre>html:lang(fr-be) | |
| 1435 html:lang(de) | |
| 1436 :lang(fr-be) > q | |
| 1437 :lang(de) > q</pre> | |
| 1438 </div> | |
| 1439 | |
| 1440 <h4><a name=UIstates>6.6.4. The UI element states pseudo-classes</a></h4> | |
| 1441 | |
| 1442 <h5><a name=enableddisabled>The :enabled and :disabled pseudo-classes</a></h5> | |
| 1443 | |
| 1444 <p>The <code>:enabled</code> pseudo-class allows authors to customize | |
| 1445 the look of user interface elements that are enabled — which the | |
| 1446 user can select or activate in some fashion (e.g. clicking on a button | |
| 1447 with a mouse). There is a need for such a pseudo-class because there | |
| 1448 is no way to programmatically specify the default appearance of say, | |
| 1449 an enabled <code>input</code> element without also specifying what it | |
| 1450 would look like when it was disabled.</p> | |
| 1451 | |
| 1452 <p>Similar to <code>:enabled</code>, <code>:disabled</code> allows the | |
| 1453 author to specify precisely how a disabled or inactive user interface | |
| 1454 element should look.</p> | |
| 1455 | |
| 1456 <p>Most elements will be neither enabled nor disabled. An element is | |
| 1457 enabled if the user can either activate it or transfer the focus to | |
| 1458 it. An element is disabled if it could be enabled, but the user cannot | |
| 1459 presently activate it or transfer focus to it.</p> | |
| 1460 | |
| 1461 | |
| 1462 <h5><a name=checked>The :checked pseudo-class</a></h5> | |
| 1463 | |
| 1464 <p>Radio and checkbox elements can be toggled by the user. Some menu | |
| 1465 items are "checked" when the user selects them. When such elements are | |
| 1466 toggled "on" the <code>:checked</code> pseudo-class applies. The | |
| 1467 <code>:checked</code> pseudo-class initially applies to such elements | |
| 1468 that have the HTML4 <code>selected</code> and <code>checked</code> | |
| 1469 attributes as described in <a | |
| 1470 href="http://www.w3.org/TR/REC-html40/interact/forms.html#h-17.2.1">Section | |
| 1471 17.2.1 of HTML4</a>, but of course the user can toggle "off" such | |
| 1472 elements in which case the <code>:checked</code> pseudo-class would no | |
| 1473 longer apply. While the <code>:checked</code> pseudo-class is dynamic | |
| 1474 in nature, and is altered by user action, since it can also be based | |
| 1475 on the presence of the semantic HTML4 <code>selected</code> and | |
| 1476 <code>checked</code> attributes, it applies to all media. | |
| 1477 | |
| 1478 | |
| 1479 <h5><a name=indeterminate>The :indeterminate pseudo-class</a></h5> | |
| 1480 | |
| 1481 <div class="note"> | |
| 1482 | |
| 1483 <p>Radio and checkbox elements can be toggled by the user, but are | |
| 1484 sometimes in an indeterminate state, neither checked nor unchecked. | |
| 1485 This can be due to an element attribute, or DOM manipulation.</p> | |
| 1486 | |
| 1487 <p>A future version of this specification may introduce an | |
| 1488 <code>:indeterminate</code> pseudo-class that applies to such elements. | |
| 1489 <!--While the <code>:indeterminate</code> pseudo-class is dynamic in | |
| 1490 nature, and is altered by user action, since it can also be based on | |
| 1491 the presence of an element attribute, it applies to all media.</p> | |
| 1492 | |
| 1493 <p>Components of a radio-group initialized with no pre-selected choice | |
| 1494 are an example of :indeterminate state.--></p> | |
| 1495 | |
| 1496 </div> | |
| 1497 | |
| 1498 | |
| 1499 <h4><a name=structural-pseudos>6.6.5. Structural pseudo-classes</a></h4> | |
| 1500 | |
| 1501 <p>Selectors introduces the concept of <dfn>structural | |
| 1502 pseudo-classes</dfn> to permit selection based on extra information that lies in | |
| 1503 the document tree but cannot be represented by other simple selectors or | |
| 1504 combinators. | |
| 1505 | |
| 1506 <p>Note that standalone pieces of PCDATA (text nodes in the DOM) are | |
| 1507 not counted when calculating the position of an element in the list of | |
| 1508 children of its parent. When calculating the position of an element in | |
| 1509 the list of children of its parent, the index numbering starts at 1. | |
| 1510 | |
| 1511 | |
| 1512 <h5><a name=root-pseudo>:root pseudo-class</a></h5> | |
| 1513 | |
| 1514 <p>The <code>:root</code> pseudo-class represents an element that is | |
| 1515 the root of the document. In HTML 4, this is always the | |
| 1516 <code>HTML</code> element. | |
| 1517 | |
| 1518 | |
| 1519 <h5><a name=nth-child-pseudo>:nth-child() pseudo-class</a></h5> | |
| 1520 | |
| 1521 <p>The | |
| 1522 <code>:nth-child(<var>a</var><code>n</code>+<var>b</var>)</code> | |
| 1523 pseudo-class notation represents an element that has | |
| 1524 <var>a</var><code>n</code>+<var>b</var>-1 siblings | |
| 1525 <strong>before</strong> it in the document tree, for a given positive | |
| 1526 integer or zero value of <code>n</code>, and has a parent element. In | |
| 1527 other words, this matches the <var>b</var>th child of an element after | |
| 1528 all the children have been split into groups of <var>a</var> elements | |
| 1529 each. For example, this allows the selectors to address every other | |
| 1530 row in a table, and could be used to alternate the color | |
| 1531 of paragraph text in a cycle of four. The <var>a</var> and | |
| 1532 <var>b</var> values must be zero, negative integers or positive | |
| 1533 integers. The index of the first child of an element is 1. | |
| 1534 | |
| 1535 <p>In addition to this, <code>:nth-child()</code> can take | |
| 1536 '<code>odd</code>' and '<code>even</code>' as arguments instead. | |
| 1537 '<code>odd</code>' has the same signification as <code>2n+1</code>, | |
| 1538 and '<code>even</code>' has the same signification as <code>2n</code>. | |
| 1539 | |
| 1540 | |
| 1541 <div class="example"> | |
| 1542 <p>Examples:</p> | |
| 1543 <pre>tr:nth-child(2n+1) /* represents every odd row of an HTML table */ | |
| 1544 tr:nth-child(odd) /* same */ | |
| 1545 tr:nth-child(2n) /* represents every even row of an HTML table */ | |
| 1546 tr:nth-child(even) /* same */ | |
| 1547 | |
| 1548 /* Alternate paragraph colours in CSS */ | |
| 1549 p:nth-child(4n+1) { color: navy; } | |
| 1550 p:nth-child(4n+2) { color: green; } | |
| 1551 p:nth-child(4n+3) { color: maroon; } | |
| 1552 p:nth-child(4n+4) { color: purple; }</pre> | |
| 1553 </div> | |
| 1554 | |
| 1555 <p>When <var>a</var>=0, no repeating is used, so for example | |
| 1556 <code>:nth-child(0n+5)</code> matches only the fifth child. When | |
| 1557 <var>a</var>=0, the <var>a</var><code>n</code> part need not be | |
| 1558 included, so the syntax simplifies to | |
| 1559 <code>:nth-child(<var>b</var>)</code> and the last example simplifies | |
| 1560 to <code>:nth-child(5)</code>. | |
| 1561 | |
| 1562 <div class="example"> | |
| 1563 <p>Examples:</p> | |
| 1564 <pre>foo:nth-child(0n+1) /* represents an element foo, first child of its pare
nt element */ | |
| 1565 foo:nth-child(1) /* same */</pre> | |
| 1566 </div> | |
| 1567 | |
| 1568 <p>When <var>a</var>=1, the number may be omitted from the rule. | |
| 1569 | |
| 1570 <div class="example"> | |
| 1571 <p>Examples:</p> | |
| 1572 <p>The following selectors are therefore equivalent:</p> | |
| 1573 <pre>bar:nth-child(1n+0) /* represents all bar elements, specificity (0,1,1) *
/ | |
| 1574 bar:nth-child(n+0) /* same */ | |
| 1575 bar:nth-child(n) /* same */ | |
| 1576 bar /* same but lower specificity (0,0,1) */</pre> | |
| 1577 </div> | |
| 1578 | |
| 1579 <p>If <var>b</var>=0, then every <var>a</var>th element is picked. In | |
| 1580 such a case, the <var>b</var> part may be omitted. | |
| 1581 | |
| 1582 <div class="example"> | |
| 1583 <p>Examples:</p> | |
| 1584 <pre>tr:nth-child(2n+0) /* represents every even row of an HTML table */ | |
| 1585 tr:nth-child(2n) /* same */</pre> | |
| 1586 </div> | |
| 1587 | |
| 1588 <p>If both <var>a</var> and <var>b</var> are equal to zero, the | |
| 1589 pseudo-class represents no element in the document tree.</p> | |
| 1590 | |
| 1591 <p>The value <var>a</var> can be negative, but only the positive | |
| 1592 values of <var>a</var><code>n</code>+<var>b</var>, for | |
| 1593 <code>n</code>≥0, may represent an element in the document | |
| 1594 tree.</p> | |
| 1595 | |
| 1596 <div class="example"> | |
| 1597 <p>Example:</p> | |
| 1598 <pre>html|tr:nth-child(-n+6) /* represents the 6 first rows of XHTML tables */<
/pre> | |
| 1599 </div> | |
| 1600 | |
| 1601 <p>When the value <var>b</var> is negative, the "+" character in the | |
| 1602 expression must be removed (it is effectively replaced by the "-" | |
| 1603 character indicating the negative value of <var>b</var>).</p> | |
| 1604 | |
| 1605 <div class="example"> | |
| 1606 <p>Examples:</p> | |
| 1607 <pre>:nth-child(10n-1) /* represents the 9th, 19th, 29th, etc, element */ | |
| 1608 :nth-child(10n+9) /* Same */ | |
| 1609 :nth-child(10n+-1) /* Syntactically invalid, and would be ignored */</pre> | |
| 1610 </div> | |
| 1611 | |
| 1612 | |
| 1613 <h5><a name=nth-last-child-pseudo>:nth-last-child() pseudo-class</a></h5> | |
| 1614 | |
| 1615 <p>The <code>:nth-last-child(<var>a</var>n+<var>b</var>)</code> | |
| 1616 pseudo-class notation represents an element that has | |
| 1617 <var>a</var><code>n</code>+<var>b</var>-1 siblings | |
| 1618 <strong>after</strong> it in the document tree, for a given positive | |
| 1619 integer or zero value of <code>n</code>, and has a parent element. See | |
| 1620 <code>:nth-child()</code> pseudo-class for the syntax of its argument. | |
| 1621 It also accepts the '<code>even</code>' and '<code>odd</code>' values | |
| 1622 as arguments. | |
| 1623 | |
| 1624 | |
| 1625 <div class="example"> | |
| 1626 <p>Examples:</p> | |
| 1627 <pre>tr:nth-last-child(-n+2) /* represents the two last rows of an HTML table
*/ | |
| 1628 | |
| 1629 foo:nth-last-child(odd) /* represents all odd foo elements in their parent el
ement, | |
| 1630 counting from the last one */</pre> | |
| 1631 </div> | |
| 1632 | |
| 1633 | |
| 1634 <h5><a name=nth-of-type-pseudo>:nth-of-type() pseudo-class</a></h5> | |
| 1635 | |
| 1636 <p>The <code>:nth-of-type(<var>a</var>n+<var>b</var>)</code> | |
| 1637 pseudo-class notation represents an element that has | |
| 1638 <var>a</var><code>n</code>+<var>b</var>-1 siblings with the same | |
| 1639 element name <strong>before</strong> it in the document tree, for a | |
| 1640 given zero or positive integer value of <code>n</code>, and has a | |
| 1641 parent element. In other words, this matches the <var>b</var>th child | |
| 1642 of that type after all the children of that type have been split into | |
| 1643 groups of a elements each. See <code>:nth-child()</code> pseudo-class | |
| 1644 for the syntax of its argument. It also accepts the | |
| 1645 '<code>even</code>' and '<code>odd</code>' values. | |
| 1646 | |
| 1647 | |
| 1648 <div class="example"> | |
| 1649 <p>CSS example:</p> | |
| 1650 <p>This allows an author to alternate the position of floated images:</p> | |
| 1651 <pre>img:nth-of-type(2n+1) { float: right; } | |
| 1652 img:nth-of-type(2n) { float: left; }</pre> | |
| 1653 </div> | |
| 1654 | |
| 1655 | |
| 1656 <h5><a name=nth-last-of-type-pseudo>:nth-last-of-type() pseudo-class</a></h5> | |
| 1657 | |
| 1658 <p>The <code>:nth-last-of-type(<var>a</var>n+<var>b</var>)</code> | |
| 1659 pseudo-class notation represents an element that has | |
| 1660 <var>a</var><code>n</code>+<var>b</var>-1 siblings with the same | |
| 1661 element name <strong>after</strong> it in the document tree, for a | |
| 1662 given zero or positive integer value of <code>n</code>, and has a | |
| 1663 parent element. See <code>:nth-child()</code> pseudo-class for the | |
| 1664 syntax of its argument. It also accepts the '<code>even</code>' and '<code>odd</
code>' values. | |
| 1665 | |
| 1666 | |
| 1667 <div class="example"> | |
| 1668 <p>Example:</p> | |
| 1669 <p>To represent all <code>h2</code> children of an XHTML | |
| 1670 <code>body</code> except the first and last, one could use the | |
| 1671 following selector:</p> | |
| 1672 <pre>body > h2:nth-of-type(n+2):nth-last-of-type(n+2)</pre> | |
| 1673 <p>In this case, one could also use <code>:not()</code>, although the | |
| 1674 selector ends up being just as long:</p> | |
| 1675 <pre>body > h2:not(:first-of-type):not(:last-of-type)</pre> | |
| 1676 </div> | |
| 1677 | |
| 1678 | |
| 1679 <h5><a name=first-child-pseudo>:first-child pseudo-class</a></h5> | |
| 1680 | |
| 1681 <p>Same as <code>:nth-child(1)</code>. The <code>:first-child</code> pseudo-clas
s | |
| 1682 represents an element that is the first child of some other element. | |
| 1683 | |
| 1684 | |
| 1685 <div class="example"> | |
| 1686 <p>Examples:</p> | |
| 1687 <p>The following selector represents a <code>p</code> element that is | |
| 1688 the first child of a <code>div</code> element:</p> | |
| 1689 <pre>div > p:first-child</pre> | |
| 1690 <p>This selector can represent the <code>p</code> inside the | |
| 1691 <code>div</code> of the following fragment:</p> | |
| 1692 <pre><p> The last P before the note.</p> | |
| 1693 <div class="note"> | |
| 1694 <p> The first P inside the note.</p> | |
| 1695 </div></pre>but cannot represent the second <code>p</code> in the followin
g | |
| 1696 fragment: | |
| 1697 <pre><p> The last P before the note.</p> | |
| 1698 <div class="note"> | |
| 1699 <h2> Note </h2> | |
| 1700 <p> The first P inside the note.</p> | |
| 1701 </div></pre> | |
| 1702 <p>The following two selectors are usually equivalent:</p> | |
| 1703 <pre>* > a:first-child /* a is first child of any element */ | |
| 1704 a:first-child /* Same (assuming a is not the root element) */</pre> | |
| 1705 </div> | |
| 1706 | |
| 1707 <h5><a name=last-child-pseudo>:last-child pseudo-class</a></h5> | |
| 1708 | |
| 1709 <p>Same as <code>:nth-last-child(1)</code>. The <code>:last-child</code> pseudo-
class | |
| 1710 represents an element that is the last child of some other element. | |
| 1711 | |
| 1712 <div class="example"> | |
| 1713 <p>Example:</p> | |
| 1714 <p>The following selector represents a list item <code>li</code> that | |
| 1715 is the last child of an ordered list <code>ol</code>. | |
| 1716 <pre>ol > li:last-child</pre> | |
| 1717 </div> | |
| 1718 | |
| 1719 <h5><a name=first-of-type-pseudo>:first-of-type pseudo-class</a></h5> | |
| 1720 | |
| 1721 <p>Same as <code>:nth-of-type(1)</code>. The <code>:first-of-type</code> pseudo-
class | |
| 1722 represents an element that is the first sibling of its type in the list of | |
| 1723 children of its parent element. | |
| 1724 | |
| 1725 <div class="example"> | |
| 1726 <p>Example:</p> | |
| 1727 <p>The following selector represents a definition title | |
| 1728 <code>dt</code> inside a definition list <code>dl</code>, this | |
| 1729 <code>dt</code> being the first of its type in the list of children of | |
| 1730 its parent element.</p> | |
| 1731 <pre>dl dt:first-of-type</pre> | |
| 1732 <p>It is a valid description for the first two <code>dt</code> | |
| 1733 elements in the following example but not for the third one:</p> | |
| 1734 <pre><dl> | |
| 1735 <dt>gigogne</dt> | |
| 1736 <dd> | |
| 1737 <dl> | |
| 1738 <dt>fusée</dt> | |
| 1739 <dd>multistage rocket</dd> | |
| 1740 <dt>table</dt> | |
| 1741 <dd>nest of tables</dd> | |
| 1742 </dl> | |
| 1743 </dd> | |
| 1744 </dl></pre> | |
| 1745 </div> | |
| 1746 | |
| 1747 <h5><a name=last-of-type-pseudo>:last-of-type pseudo-class</a></h5> | |
| 1748 | |
| 1749 <p>Same as <code>:nth-last-of-type(1)</code>. The | |
| 1750 <code>:last-of-type</code> pseudo-class represents an element that is | |
| 1751 the last sibling of its type in the list of children of its parent | |
| 1752 element.</p> | |
| 1753 | |
| 1754 <div class="example"> | |
| 1755 <p>Example:</p> | |
| 1756 <p>The following selector represents the last data cell | |
| 1757 <code>td</code> of a table row.</p> | |
| 1758 <pre>tr > td:last-of-type</pre> | |
| 1759 </div> | |
| 1760 | |
| 1761 <h5><a name=only-child-pseudo>:only-child pseudo-class</a></h5> | |
| 1762 | |
| 1763 <p>Represents an element that has a parent element and whose parent | |
| 1764 element has no other element children. Same as | |
| 1765 <code>:first-child:last-child</code> or | |
| 1766 <code>:nth-child(1):nth-last-child(1)</code>, but with a lower | |
| 1767 specificity.</p> | |
| 1768 | |
| 1769 <h5><a name=only-of-type-pseudo>:only-of-type pseudo-class</a></h5> | |
| 1770 | |
| 1771 <p>Represents an element that has a parent element and whose parent | |
| 1772 element has no other element children with the same element name. Same | |
| 1773 as <code>:first-of-type:last-of-type</code> or | |
| 1774 <code>:nth-of-type(1):nth-last-of-type(1)</code>, but with a lower | |
| 1775 specificity.</p> | |
| 1776 | |
| 1777 | |
| 1778 <h5><a name=empty-pseudo></a>:empty pseudo-class</h5> | |
| 1779 | |
| 1780 <p>The <code>:empty</code> pseudo-class represents an element that has | |
| 1781 no children at all. In terms of the DOM, only element nodes and text | |
| 1782 nodes (including CDATA nodes and entity references) whose data has a | |
| 1783 non-zero length must be considered as affecting emptiness; comments, | |
| 1784 PIs, and other nodes must not affect whether an element is considered | |
| 1785 empty or not.</p> | |
| 1786 | |
| 1787 <div class="example"> | |
| 1788 <p>Examples:</p> | |
| 1789 <p><code>p:empty</code> is a valid representation of the following fragment:</p
> | |
| 1790 <pre><p></p></pre> | |
| 1791 <p><code>foo:empty</code> is not a valid representation for the | |
| 1792 following fragments:</p> | |
| 1793 <pre><foo>bar</foo></pre> | |
| 1794 <pre><foo><bar>bla</bar></foo></pre> | |
| 1795 <pre><foo>this is not <bar>:empty</bar></foo></pre> | |
| 1796 </div> | |
| 1797 | |
| 1798 <h4><a name=content-selectors>6.6.6. Blank</a></h4> <!-- It's the Return of Appe
ndix H!!! Run away! --> | |
| 1799 | |
| 1800 <p>This section intentionally left blank.</p> | |
| 1801 <!-- (used to be :contains()) --> | |
| 1802 | |
| 1803 <h4><a name=negation></a>6.6.7. The negation pseudo-class</h4> | |
| 1804 | |
| 1805 <p>The negation pseudo-class, <code>:not(<var>X</var>)</code>, is a | |
| 1806 functional notation taking a <a href="#simple-selectors-dfn">simple | |
| 1807 selector</a> (excluding the negation pseudo-class itself and | |
| 1808 pseudo-elements) as an argument. It represents an element that is not | |
| 1809 represented by the argument. | |
| 1810 | |
| 1811 <!-- pseudo-elements are not simple selectors, so the above paragraph | |
| 1812 may be a bit confusing --> | |
| 1813 | |
| 1814 <div class="example"> | |
| 1815 <p>Examples:</p> | |
| 1816 <p>The following CSS selector matches all <code>button</code> | |
| 1817 elements in an HTML document that are not disabled.</p> | |
| 1818 <pre>button:not([DISABLED])</pre> | |
| 1819 <p>The following selector represents all but <code>FOO</code> | |
| 1820 elements.</p> | |
| 1821 <pre>*:not(FOO)</pre> | |
| 1822 <p>The following group of selectors represents all HTML elements | |
| 1823 except links.</p> | |
| 1824 <pre>html|*:not(:link):not(:visited)</pre> | |
| 1825 </div> | |
| 1826 | |
| 1827 <p>Default namespace declarations do not affect the argument of the | |
| 1828 negation pseudo-class unless the argument is a universal selector or a | |
| 1829 type selector.</p> | |
| 1830 | |
| 1831 <div class="example"> | |
| 1832 <p>Examples:</p> | |
| 1833 <p>Assuming that the default namespace is bound to | |
| 1834 "http://example.com/", the following selector represents all | |
| 1835 elements that are not in that namespace:</p> | |
| 1836 <pre>*|*:not(*)</pre> | |
| 1837 <p>The following CSS selector matches any element being hovered, | |
| 1838 regardless of its namespace. In particular, it is not limited to | |
| 1839 only matching elements in the default namespace that are not being | |
| 1840 hovered, and elements not in the default namespace don't match the | |
| 1841 rule when they <em>are</em> being hovered.</p> | |
| 1842 <pre>*|*:not(:hover)</pre> | |
| 1843 </div> | |
| 1844 | |
| 1845 <p class="note"><strong>Note</strong>: the :not() pseudo allows | |
| 1846 useless selectors to be written. For instance <code>:not(*|*)</code>, | |
| 1847 which represents no element at all, or <code>foo:not(bar)</code>, | |
| 1848 which is equivalent to <code>foo</code> but with a higher | |
| 1849 specificity.</p> | |
| 1850 | |
| 1851 <h3><a name=pseudo-elements>7. Pseudo-elements</a></h3> | |
| 1852 | |
| 1853 <p>Pseudo-elements create abstractions about the document tree beyond | |
| 1854 those specified by the document language. For instance, document | |
| 1855 languages do not offer mechanisms to access the first letter or first | |
| 1856 line of an element's content. Pseudo-elements allow designers to refer | |
| 1857 to this otherwise inaccessible information. Pseudo-elements may also | |
| 1858 provide designers a way to refer to content that does not exist in the | |
| 1859 source document (e.g., the <code>::before</code> and | |
| 1860 <code>::after</code> pseudo-elements give access to generated | |
| 1861 content).</p> | |
| 1862 | |
| 1863 <p>A pseudo-element is made of two colons (<code>::</code>) followed | |
| 1864 by the name of the pseudo-element.</p> | |
| 1865 | |
| 1866 <p>This <code>::</code> notation is introduced by the current document | |
| 1867 in order to establish a discrimination between pseudo-classes and | |
| 1868 pseudo-elements. For compatibility with existing style sheets, user | |
| 1869 agents must also accept the previous one-colon notation for | |
| 1870 pseudo-elements introduced in CSS levels 1 and 2 (namely, | |
| 1871 <code>:first-line</code>, <code>:first-letter</code>, | |
| 1872 <code>:before</code> and <code>:after</code>). This compatibility is | |
| 1873 not allowed for the new pseudo-elements introduced in CSS level 3.</p> | |
| 1874 | |
| 1875 <p>Only one pseudo-element may appear per selector, and if present it | |
| 1876 must appear after the sequence of simple selectors that represents the | |
| 1877 <a href="#subject">subjects</a> of the selector. <span class="note">A | |
| 1878 future version of this specification may allow multiple | |
| 1879 pesudo-elements per selector.</span></p> | |
| 1880 | |
| 1881 <h4><a name=first-line>7.1. The ::first-line pseudo-element</a></h4> | |
| 1882 | |
| 1883 <p>The <code>::first-line</code> pseudo-element describes the contents | |
| 1884 of the first formatted line of an element. | |
| 1885 | |
| 1886 <div class="example"> | |
| 1887 <p>CSS example:</p> | |
| 1888 <pre>p::first-line { text-transform: uppercase }</pre> | |
| 1889 <p>The above rule means "change the letters of the first line of every | |
| 1890 paragraph to uppercase".</p> | |
| 1891 </div> | |
| 1892 | |
| 1893 <p>The selector <code>p::first-line</code> does not match any real | |
| 1894 HTML element. It does match a pseudo-element that conforming user | |
| 1895 agents will insert at the beginning of every paragraph.</p> | |
| 1896 | |
| 1897 <p>Note that the length of the first line depends on a number of | |
| 1898 factors, including the width of the page, the font size, etc. Thus, | |
| 1899 an ordinary HTML paragraph such as:</p> | |
| 1900 | |
| 1901 <pre> | |
| 1902 <P>This is a somewhat long HTML | |
| 1903 paragraph that will be broken into several | |
| 1904 lines. The first line will be identified | |
| 1905 by a fictional tag sequence. The other lines | |
| 1906 will be treated as ordinary lines in the | |
| 1907 paragraph.</P> | |
| 1908 </pre> | |
| 1909 | |
| 1910 <p>the lines of which happen to be broken as follows: | |
| 1911 | |
| 1912 <pre> | |
| 1913 THIS IS A SOMEWHAT LONG HTML PARAGRAPH THAT | |
| 1914 will be broken into several lines. The first | |
| 1915 line will be identified by a fictional tag | |
| 1916 sequence. The other lines will be treated as | |
| 1917 ordinary lines in the paragraph. | |
| 1918 </pre> | |
| 1919 | |
| 1920 <p>This paragraph might be "rewritten" by user agents to include the | |
| 1921 <em>fictional tag sequence</em> for <code>::first-line</code>. This | |
| 1922 fictional tag sequence helps to show how properties are inherited.</p> | |
| 1923 | |
| 1924 <pre> | |
| 1925 <P><b><P::first-line></b> This is a somewhat long HTML | |
| 1926 paragraph that <b></P::first-line></b> will be broken into several | |
| 1927 lines. The first line will be identified | |
| 1928 by a fictional tag sequence. The other lines | |
| 1929 will be treated as ordinary lines in the | |
| 1930 paragraph.</P> | |
| 1931 </pre> | |
| 1932 | |
| 1933 <p>If a pseudo-element breaks up a real element, the desired effect | |
| 1934 can often be described by a fictional tag sequence that closes and | |
| 1935 then re-opens the element. Thus, if we mark up the previous paragraph | |
| 1936 with a <code>span</code> element:</p> | |
| 1937 | |
| 1938 <pre> | |
| 1939 <P><b><SPAN class="test"></b> This is a somewhat long HTML | |
| 1940 paragraph that will be broken into several | |
| 1941 lines.<b></SPAN></b> The first line will be identified | |
| 1942 by a fictional tag sequence. The other lines | |
| 1943 will be treated as ordinary lines in the | |
| 1944 paragraph.</P> | |
| 1945 </pre> | |
| 1946 | |
| 1947 <p>the user agent could simulate start and end tags for | |
| 1948 <code>span</code> when inserting the fictional tag sequence for | |
| 1949 <code>::first-line</code>. | |
| 1950 | |
| 1951 <pre> | |
| 1952 <P><P::first-line><b><SPAN class="test"></b> This is a | |
| 1953 somewhat long HTML | |
| 1954 paragraph that will <b></SPAN></b></P::first-line><b><SPAN class=
"test"></b> be | |
| 1955 broken into several | |
| 1956 lines.<b></SPAN></b> The first line will be identified | |
| 1957 by a fictional tag sequence. The other lines | |
| 1958 will be treated as ordinary lines in the | |
| 1959 paragraph.</P> | |
| 1960 </pre> | |
| 1961 | |
| 1962 <p>In CSS, the <code>::first-line</code> pseudo-element can only be | |
| 1963 attached to a block-level element, an inline-block, a table-caption, | |
| 1964 or a table-cell.</p> | |
| 1965 | |
| 1966 <p><a name="first-formatted-line"></a>The "first formatted line" of an | |
| 1967 element may occur inside a | |
| 1968 block-level descendant in the same flow (i.e., a block-level | |
| 1969 descendant that is not positioned and not a float). E.g., the first | |
| 1970 line of the <code>div</code> in <code><DIV><P>This | |
| 1971 line...</P></DIV></code> is the first line of the <code>p</code> (assuming | |
| 1972 that both <code>p</code> and <code>div</code> are block-level). | |
| 1973 | |
| 1974 <p>The first line of a table-cell or inline-block cannot be the first | |
| 1975 formatted line of an ancestor element. Thus, in <code><DIV><P | |
| 1976 STYLE="display: inline-block">Hello<BR>Goodbye</P> | |
| 1977 etcetera</DIV></code> the first formatted line of the | |
| 1978 <code>div</code> is not the line "Hello". | |
| 1979 | |
| 1980 <p class="note">Note that the first line of the <code>p</code> in this | |
| 1981 fragment: <code><p><br>First...</code> doesn't contain any | |
| 1982 letters (assuming the default style for <code>br</code> in HTML | |
| 1983 4). The word "First" is not on the first formatted line. | |
| 1984 | |
| 1985 <p>A UA should act as if the fictional start tags of the | |
| 1986 <code>::first-line</code> pseudo-elements were nested just inside the | |
| 1987 innermost enclosing block-level element. (Since CSS1 and CSS2 were | |
| 1988 silent on this case, authors should not rely on this behavior.) Here | |
| 1989 is an example. The fictional tag sequence for</p> | |
| 1990 | |
| 1991 <pre> | |
| 1992 <DIV> | |
| 1993 <P>First paragraph</P> | |
| 1994 <P>Second paragraph</P> | |
| 1995 </DIV> | |
| 1996 </pre> | |
| 1997 | |
| 1998 <p>is</p> | |
| 1999 | |
| 2000 <pre> | |
| 2001 <DIV> | |
| 2002 <P><DIV::first-line><P::first-line>First paragraph</P::first-line>
</DIV::first-line></P> | |
| 2003 <P><P::first-line>Second paragraph</P::first-line></P> | |
| 2004 </DIV> | |
| 2005 </pre> | |
| 2006 | |
| 2007 <p>The <code>::first-line</code> pseudo-element is similar to an | |
| 2008 inline-level element, but with certain restrictions. In CSS, the | |
| 2009 following properties apply to a <code>::first-line</code> | |
| 2010 pseudo-element: font properties, color property, background | |
| 2011 properties, 'word-spacing', 'letter-spacing', 'text-decoration', | |
| 2012 'vertical-align', 'text-transform', 'line-height'. UAs may apply other | |
| 2013 properties as well.</p> | |
| 2014 | |
| 2015 | |
| 2016 <h4><a name=first-letter>7.2. The ::first-letter pseudo-element</a></h4> | |
| 2017 | |
| 2018 <p>The <code>::first-letter</code> pseudo-element represents the first | |
| 2019 letter of the first line of a block, if it is not preceded by any | |
| 2020 other content (such as images or inline tables) on its line. The | |
| 2021 ::first-letter pseudo-element may be used for "initial caps" and "drop | |
| 2022 caps", which are common typographical effects. This type of initial | |
| 2023 letter is similar to an inline-level element if its 'float' property | |
| 2024 is 'none'; otherwise, it is similar to a floated element.</p> | |
| 2025 | |
| 2026 <p>In CSS, these are the properties that apply to <code>::first-letter</code> | |
| 2027 pseudo-elements: font properties, 'text-decoration', 'text-transform', | |
| 2028 'letter-spacing', 'word-spacing' (when appropriate), 'line-height', | |
| 2029 'float', 'vertical-align' (only if 'float' is 'none'), margin | |
| 2030 properties, padding properties, border properties, color property, | |
| 2031 background properties. UAs may apply other properties as well. To | |
| 2032 allow UAs to render a typographically correct drop cap or initial cap, | |
| 2033 the UA may choose a line-height, width and height based on the shape | |
| 2034 of the letter, unlike for normal elements.</p> | |
| 2035 | |
| 2036 <div class="example"> | |
| 2037 <p>Example:</p> | |
| 2038 <p>This example shows a possible rendering of an initial cap. Note | |
| 2039 that the 'line-height' that is inherited by the <code>::first-letter</code> | |
| 2040 pseudo-element is 1.1, but the UA in this example has computed the | |
| 2041 height of the first letter differently, so that it doesn't cause any | |
| 2042 unnecessary space between the first two lines. Also note that the | |
| 2043 fictional start tag of the first letter is inside the <span>span</span>, and thu
s | |
| 2044 the font weight of the first letter is normal, not bold as the <span>span</span>
: | |
| 2045 <pre> | |
| 2046 p { line-height: 1.1 } | |
| 2047 p::first-letter { font-size: 3em; font-weight: normal } | |
| 2048 span { font-weight: bold } | |
| 2049 ... | |
| 2050 <p><span>Het hemelsche</span> gerecht heeft zich ten lange lesten<br
> | |
| 2051 Erbarremt over my en mijn benaeuwde vesten<br> | |
| 2052 En arme burgery, en op mijn volcx gebed<br> | |
| 2053 En dagelix geschrey de bange stad ontzet. | |
| 2054 </pre> | |
| 2055 <div class="figure"> | |
| 2056 <p><img src="initial-cap.png" alt="Image illustrating the ::first-letter pseudo-
element"> | |
| 2057 </div> | |
| 2058 </div> | |
| 2059 | |
| 2060 <div class="example"> | |
| 2061 <p>The following CSS will make a drop cap initial letter span about two lines:</
p> | |
| 2062 | |
| 2063 <pre> | |
| 2064 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> | |
| 2065 <HTML> | |
| 2066 <HEAD> | |
| 2067 <TITLE>Drop cap initial letter</TITLE> | |
| 2068 <STYLE type="text/css"> | |
| 2069 P { font-size: 12pt; line-height: 1.2 } | |
| 2070 P::first-letter { font-size: 200%; font-weight: bold; float: left } | |
| 2071 SPAN { text-transform: uppercase } | |
| 2072 </STYLE> | |
| 2073 </HEAD> | |
| 2074 <BODY> | |
| 2075 <P><SPAN>The first</SPAN> few words of an article | |
| 2076 in The Economist.</P> | |
| 2077 </BODY> | |
| 2078 </HTML> | |
| 2079 </pre> | |
| 2080 | |
| 2081 <p>This example might be formatted as follows:</p> | |
| 2082 | |
| 2083 <div class="figure"> | |
| 2084 <P><img src="first-letter.gif" alt="Image illustrating the combined effect of th
e ::first-letter and ::first-line pseudo-elements"></p> | |
| 2085 </div> | |
| 2086 | |
| 2087 <p>The <span class="index-inst" title="fictional tag | |
| 2088 sequence">fictional tag sequence</span> is:</p> | |
| 2089 | |
| 2090 <pre> | |
| 2091 <P> | |
| 2092 <SPAN> | |
| 2093 <P::first-letter> | |
| 2094 T | |
| 2095 </P::first-letter>he first | |
| 2096 </SPAN> | |
| 2097 few words of an article in the Economist. | |
| 2098 </P> | |
| 2099 </pre> | |
| 2100 | |
| 2101 <p>Note that the <code>::first-letter</code> pseudo-element tags abut | |
| 2102 the content (i.e., the initial character), while the ::first-line | |
| 2103 pseudo-element start tag is inserted right after the start tag of the | |
| 2104 block element.</p> </div> | |
| 2105 | |
| 2106 <p>In order to achieve traditional drop caps formatting, user agents | |
| 2107 may approximate font sizes, for example to align baselines. Also, the | |
| 2108 glyph outline may be taken into account when formatting.</p> | |
| 2109 | |
| 2110 <p>Punctuation (i.e, characters defined in Unicode in the "open" (Ps), | |
| 2111 "close" (Pe), "initial" (Pi). "final" (Pf) and "other" (Po) | |
| 2112 punctuation classes), that precedes or follows the first letter should | |
| 2113 be included. <a href="#refsUNICODE">[UNICODE]</a></p> | |
| 2114 | |
| 2115 <div class="figure"> | |
| 2116 <P><img src="first-letter2.gif" alt="Quotes that precede the | |
| 2117 first letter should be included."></p> | |
| 2118 </div> | |
| 2119 | |
| 2120 <p>The <code>::first-letter</code> also applies if the first letter is | |
| 2121 in fact a digit, e.g., the "6" in "67 million dollars is a lot of | |
| 2122 money."</p> | |
| 2123 | |
| 2124 <p>In CSS, the <code>::first-letter</code> pseudo-element applies to | |
| 2125 block, list-item, table-cell, table-caption, and inline-block | |
| 2126 elements. <span class="note">A future version of this specification | |
| 2127 may allow this pesudo-element to apply to more element | |
| 2128 types.</span></p> | |
| 2129 | |
| 2130 <p>The <code>::first-letter</code> pseudo-element can be used with all | |
| 2131 such elements that contain text, or that have a descendant in the same | |
| 2132 flow that contains text. A UA should act as if the fictional start tag | |
| 2133 of the ::first-letter pseudo-element is just before the first text of | |
| 2134 the element, even if that first text is in a descendant.</p> | |
| 2135 | |
| 2136 <div class="example"> | |
| 2137 <p>Example:</p> | |
| 2138 <p>The fictional tag sequence for this HTMLfragment: | |
| 2139 <pre><div> | |
| 2140 <p>The first text.</pre> | |
| 2141 <p>is: | |
| 2142 <pre><div> | |
| 2143 <p><div::first-letter><p::first-letter>T</...></...>he first text
.</pre> | |
| 2144 </div> | |
| 2145 | |
| 2146 <p>The first letter of a table-cell or inline-block cannot be the | |
| 2147 first letter of an ancestor element. Thus, in <code><DIV><P | |
| 2148 STYLE="display: inline-block">Hello<BR>Goodbye</P> | |
| 2149 etcetera</DIV></code> the first letter of the <code>div</code> is not the | |
| 2150 letter "H". In fact, the <code>div</code> doesn't have a first letter. | |
| 2151 | |
| 2152 <p>The first letter must occur on the <a | |
| 2153 href="#first-formatted-line">first formatted line.</a> For example, in | |
| 2154 this fragment: <code><p><br>First...</code> the first line | |
| 2155 doesn't contain any letters and <code>::first-letter</code> doesn't | |
| 2156 match anything (assuming the default style for <code>br</code> in HTML | |
| 2157 4). In particular, it does not match the "F" of "First." | |
| 2158 | |
| 2159 <p>In CSS, if an element is a list item ('display: list-item'), the | |
| 2160 <code>::first-letter</code> applies to the first letter in the | |
| 2161 principal box after the marker. UAs may ignore | |
| 2162 <code>::first-letter</code> on list items with 'list-style-position: | |
| 2163 inside'. If an element has <code>::before</code> or | |
| 2164 <code>::after</code> content, the <code>::first-letter</code> applies | |
| 2165 to the first letter of the element <em>including</em> that content. | |
| 2166 | |
| 2167 <div class="example"> | |
| 2168 <p>Example:</p> | |
| 2169 <p>After the rule 'p::before {content: "Note: "}', the selector | |
| 2170 'p::first-letter' matches the "N" of "Note".</p> | |
| 2171 </div> | |
| 2172 | |
| 2173 <p>Some languages may have specific rules about how to treat certain | |
| 2174 letter combinations. In Dutch, for example, if the letter combination | |
| 2175 "ij" appears at the beginning of a word, both letters should be | |
| 2176 considered within the <code>::first-letter</code> pseudo-element. | |
| 2177 | |
| 2178 <p>If the letters that would form the ::first-letter are not in the | |
| 2179 same element, such as "'T" in <code><p>'<em>T...</code>, the UA | |
| 2180 may create a ::first-letter pseudo-element from one of the elements, | |
| 2181 both elements, or simply not create a pseudo-element.</p> | |
| 2182 | |
| 2183 <p>Similarly, if the first letter(s) of the block are not at the start | |
| 2184 of the line (for example due to bidirectional reordering), then the UA | |
| 2185 need not create the pseudo-element(s). | |
| 2186 | |
| 2187 <div class="example"> | |
| 2188 <p>Example:</p> | |
| 2189 <p><a name="overlapping-example">The following example</a> illustrates | |
| 2190 how overlapping pseudo-elements may interact. The first letter of | |
| 2191 each P element will be green with a font size of '24pt'. The rest of | |
| 2192 the first formatted line will be 'blue' while the rest of the | |
| 2193 paragraph will be 'red'.</p> | |
| 2194 | |
| 2195 <pre>p { color: red; font-size: 12pt } | |
| 2196 p::first-letter { color: green; font-size: 200% } | |
| 2197 p::first-line { color: blue } | |
| 2198 | |
| 2199 <P>Some text that ends up on two lines</P></pre> | |
| 2200 | |
| 2201 <p>Assuming that a line break will occur before the word "ends", the | |
| 2202 <span class="index-inst" title="fictional tag sequence">fictional tag | |
| 2203 sequence</span> for this fragment might be:</p> | |
| 2204 | |
| 2205 <pre><P> | |
| 2206 <P::first-line> | |
| 2207 <P::first-letter> | |
| 2208 S | |
| 2209 </P::first-letter>ome text that | |
| 2210 </P::first-line> | |
| 2211 ends up on two lines | |
| 2212 </P></pre> | |
| 2213 | |
| 2214 <p>Note that the <code>::first-letter</code> element is inside the <code>::first
-line</code> | |
| 2215 element. Properties set on <code>::first-line</code> are inherited by | |
| 2216 <code>::first-letter</code>, but are overridden if the same property is set on | |
| 2217 <code>::first-letter</code>.</p> | |
| 2218 </div> | |
| 2219 | |
| 2220 | |
| 2221 <h4><a name=UIfragments>7.3.</a> <a name=selection>The ::selection pseudo-elemen
t</a></h4> | |
| 2222 | |
| 2223 <p>The <code>::selection</code> pseudo-element applies to the portion | |
| 2224 of a document that has been highlighted by the user. This also | |
| 2225 applies, for example, to selected text within an editable text | |
| 2226 field. This pseudo-element should not be confused with the <code><a | |
| 2227 href="#checked">:checked</a></code> pseudo-class (which used to be | |
| 2228 named <code>:selected</code>) | |
| 2229 | |
| 2230 <p>Although the <code>::selection</code> pseudo-element is dynamic in | |
| 2231 nature, and is altered by user action, it is reasonable to expect that | |
| 2232 when a UA re-renders to a static medium (such as a printed page, see | |
| 2233 <a href="#refsCSS21">[CSS21]</a>) which was originally rendered to a | |
| 2234 dynamic medium (like screen), the UA may wish to transfer the current | |
| 2235 <code>::selection</code> state to that other medium, and have all the | |
| 2236 appropriate formatting and rendering take effect as well. This is not | |
| 2237 required — UAs may omit the <code>::selection</code> | |
| 2238 pseudo-element for static media. | |
| 2239 | |
| 2240 <p>These are the CSS properties that apply to <code>::selection</code> | |
| 2241 pseudo-elements: color, background, cursor (optional), outline | |
| 2242 (optional). The computed value of the 'background-image' property on | |
| 2243 <code>::selection</code> may be ignored. | |
| 2244 | |
| 2245 | |
| 2246 <h4><a name=gen-content>7.4. The ::before and ::after pseudo-elements</a></h4> | |
| 2247 | |
| 2248 <p>The <code>::before</code> and <code>::after</code> pseudo-elements | |
| 2249 can be used to describe generated content before or after an element's | |
| 2250 content. They are explained in CSS 2.1 <a | |
| 2251 href="#refsCSS21">[CSS21]</a>.</p> | |
| 2252 | |
| 2253 <p>When the <code>::first-letter</code> and <code>::first-line</code> | |
| 2254 pseudo-elements are combined with <code>::before</code> and | |
| 2255 <code>::after</code>, they apply to the first letter or line of the | |
| 2256 element including the inserted text.</p> | |
| 2257 | |
| 2258 <h2><a name=combinators>8. Combinators</a></h2> | |
| 2259 | |
| 2260 <h3><a name=descendant-combinators>8.1. Descendant combinator</a></h3> | |
| 2261 | |
| 2262 <p>At times, authors may want selectors to describe an element that is | |
| 2263 the descendant of another element in the document tree (e.g., "an | |
| 2264 <code>EM</code> element that is contained within an <code>H1</code> | |
| 2265 element"). Descendant combinators express such a relationship. A | |
| 2266 descendant combinator is <a href="#whitespace">white space</a> that | |
| 2267 separates two sequences of simple selectors. A selector of the form | |
| 2268 "<code>A B</code>" represents an element <code>B</code> that is an | |
| 2269 arbitrary descendant of some ancestor element <code>A</code>. | |
| 2270 | |
| 2271 <div class="example"> | |
| 2272 <p>Examples:</p> | |
| 2273 <p>For example, consider the following selector:</p> | |
| 2274 <pre>h1 em</pre> | |
| 2275 <p>It represents an <code>em</code> element being the descendant of | |
| 2276 an <code>h1</code> element. It is a correct and valid, but partial, | |
| 2277 description of the following fragment:</p> | |
| 2278 <pre><h1>This <span class="myclass">headline | |
| 2279 is <em>very</em> important</span></h1></pre> | |
| 2280 <p>The following selector:</p> | |
| 2281 <pre>div * p</pre> | |
| 2282 <p>represents a <code>p</code> element that is a grandchild or later | |
| 2283 descendant of a <code>div</code> element. Note the whitespace on | |
| 2284 either side of the "*" is not part of the universal selector; the | |
| 2285 whitespace is a combinator indicating that the DIV must be the | |
| 2286 ancestor of some element, and that that element must be an ancestor | |
| 2287 of the P.</p> | |
| 2288 <p>The following selector, which combines descendant combinators and | |
| 2289 <a href="#attribute-selectors">attribute selectors</a>, represents an | |
| 2290 element that (1) has the <code>href</code> attribute set and (2) is | |
| 2291 inside a <code>p</code> that is itself inside a <code>div</code>:</p> | |
| 2292 <pre>div p *[href]</pre> | |
| 2293 </div> | |
| 2294 | |
| 2295 <h3><a name=child-combinators>8.2. Child combinators</a></h3> | |
| 2296 | |
| 2297 <p>A <dfn>child combinator</dfn> describes a childhood relationship | |
| 2298 between two elements. A child combinator is made of the | |
| 2299 "greater-than sign" (<code>></code>) character and | |
| 2300 separates two sequences of simple selectors. | |
| 2301 | |
| 2302 | |
| 2303 <div class="example"> | |
| 2304 <p>Examples:</p> | |
| 2305 <p>The following selector represents a <code>p</code> element that is | |
| 2306 child of <code>body</code>:</p> | |
| 2307 <pre>body > p</pre> | |
| 2308 <p>The following example combines descendant combinators and child | |
| 2309 combinators.</p> | |
| 2310 <pre>div ol>li p</pre><!-- LEAVE THOSE SPACES OUT! see below --> | |
| 2311 <p>It represents a <code>p</code> element that is a descendant of an | |
| 2312 <code>li</code> element; the <code>li</code> element must be the | |
| 2313 child of an <code>ol</code> element; the <code>ol</code> element must | |
| 2314 be a descendant of a <code>div</code>. Notice that the optional white | |
| 2315 space around the ">" combinator has been left out.</p> | |
| 2316 </div> | |
| 2317 | |
| 2318 <p>For information on selecting the first child of an element, please | |
| 2319 see the section on the <code><a | |
| 2320 href="#structural-pseudos">:first-child</a></code> pseudo-class | |
| 2321 above.</p> | |
| 2322 | |
| 2323 <h3><a name=sibling-combinators>8.3. Sibling combinators</a></h3> | |
| 2324 | |
| 2325 <p>There are two different sibling combinators: the adjacent sibling | |
| 2326 combinator and the general sibling combinator. In both cases, | |
| 2327 non-element nodes (e.g. text between elements) are ignored when | |
| 2328 considering adjacency of elements.</p> | |
| 2329 | |
| 2330 <h4><a name=adjacent-sibling-combinators>8.3.1. Adjacent sibling combinator</a><
/h4> | |
| 2331 | |
| 2332 <p>The adjacent sibling combinator is made of the "plus | |
| 2333 sign" (U+002B, <code>+</code>) character that separates two | |
| 2334 sequences of simple selectors. The elements represented by the two | |
| 2335 sequences share the same parent in the document tree and the element | |
| 2336 represented by the first sequence immediately precedes the element | |
| 2337 represented by the second one.</p> | |
| 2338 | |
| 2339 <div class="example"> | |
| 2340 <p>Examples:</p> | |
| 2341 <p>The following selector represents a <code>p</code> element | |
| 2342 immediately following a <code>math</code> element:</p> | |
| 2343 <pre>math + p</pre> | |
| 2344 <p>The following selector is conceptually similar to the one in the | |
| 2345 previous example, except that it adds an attribute selector — it | |
| 2346 adds a constraint to the <code>h1</code> element, that it must have | |
| 2347 <code>class="opener"</code>:</p> | |
| 2348 <pre>h1.opener + h2</pre> | |
| 2349 </div> | |
| 2350 | |
| 2351 | |
| 2352 <h4><a name=general-sibling-combinators>8.3.2. General sibling combinator</a></h
4> | |
| 2353 | |
| 2354 <p>The general sibling combinator is made of the "tilde" | |
| 2355 (U+007E, <code>~</code>) character that separates two sequences of | |
| 2356 simple selectors. The elements represented by the two sequences share | |
| 2357 the same parent in the document tree and the element represented by | |
| 2358 the first sequence precedes (not necessarily immediately) the element | |
| 2359 represented by the second one.</p> | |
| 2360 | |
| 2361 <div class="example"> | |
| 2362 <p>Example:</p> | |
| 2363 <pre>h1 ~ pre</pre> | |
| 2364 <p>represents a <code>pre</code> element following an <code>h1</code>. It | |
| 2365 is a correct and valid, but partial, description of:</p> | |
| 2366 <pre><h1>Definition of the function a</h1> | |
| 2367 <p>Function a(x) has to be applied to all figures in the table.</p> | |
| 2368 <pre>function a(x) = 12x/13.5</pre></pre> | |
| 2369 </div> | |
| 2370 | |
| 2371 <h2><a name=specificity>9. Calculating a selector's specificity</a></h2> | |
| 2372 | |
| 2373 <p>A selector's specificity is calculated as follows:</p> | |
| 2374 | |
| 2375 <ul> | |
| 2376 <li>count the number of ID selectors in the selector (= a)</li> | |
| 2377 <li>count the number of class selectors, attributes selectors, and pseudo-clas
ses in the selector (= b)</li> | |
| 2378 <li>count the number of element names in the selector (= c)</li> | |
| 2379 <li>ignore pseudo-elements</li> | |
| 2380 </ul> | |
| 2381 | |
| 2382 <p>Selectors inside <a href="#negation">the negation pseudo-class</a> | |
| 2383 are counted like any other, but the negation itself does not count as | |
| 2384 a pseudo-class.</p> | |
| 2385 | |
| 2386 <p>Concatenating the three numbers a-b-c (in a number system with a | |
| 2387 large base) gives the specificity.</p> | |
| 2388 | |
| 2389 <div class="example"> | |
| 2390 <p>Examples:</p> | |
| 2391 <pre>* /* a=0 b=0 c=0 -> specificity = 0 */ | |
| 2392 LI /* a=0 b=0 c=1 -> specificity = 1 */ | |
| 2393 UL LI /* a=0 b=0 c=2 -> specificity = 2 */ | |
| 2394 UL OL+LI /* a=0 b=0 c=3 -> specificity = 3 */ | |
| 2395 H1 + *[REL=up] /* a=0 b=1 c=1 -> specificity = 11 */ | |
| 2396 UL OL LI.red /* a=0 b=1 c=3 -> specificity = 13 */ | |
| 2397 LI.red.level /* a=0 b=2 c=1 -> specificity = 21 */ | |
| 2398 #x34y /* a=1 b=0 c=0 -> specificity = 100 */ | |
| 2399 #s12:not(FOO) /* a=1 b=0 c=1 -> specificity = 101 */ | |
| 2400 </pre> | |
| 2401 </div> | |
| 2402 | |
| 2403 <p class="note"><strong>Note:</strong> the specificity of the styles | |
| 2404 specified in an HTML <code>style</code> attribute is described in CSS | |
| 2405 2.1. <a href="#refsCSS21">[CSS21]</a>.</p> | |
| 2406 | |
| 2407 <h2><a name=w3cselgrammar>10. The grammar of Selectors</a></h2> | |
| 2408 | |
| 2409 <h3><a name=grammar>10.1. Grammar</a></h3> | |
| 2410 | |
| 2411 <p>The grammar below defines the syntax of Selectors. It is globally | |
| 2412 LL(1) and can be locally LL(2) (but note that most UA's should not use | |
| 2413 it directly, since it doesn't express the parsing conventions). The | |
| 2414 format of the productions is optimized for human consumption and some | |
| 2415 shorthand notations beyond Yacc (see <a href="#refsYACC">[YACC]</a>) | |
| 2416 are used:</p> | |
| 2417 | |
| 2418 <ul> | |
| 2419 <li><b>*</b>: 0 or more | |
| 2420 <li><b>+</b>: 1 or more | |
| 2421 <li><b>?</b>: 0 or 1 | |
| 2422 <li><b>|</b>: separates alternatives | |
| 2423 <li><b>[ ]</b>: grouping </li> | |
| 2424 </ul> | |
| 2425 | |
| 2426 <p>The productions are:</p> | |
| 2427 | |
| 2428 <pre>selectors_group | |
| 2429 : selector [ COMMA S* selector ]* | |
| 2430 ; | |
| 2431 | |
| 2432 selector | |
| 2433 : simple_selector_sequence [ combinator simple_selector_sequence ]* | |
| 2434 ; | |
| 2435 | |
| 2436 combinator | |
| 2437 /* combinators can be surrounded by white space */ | |
| 2438 : PLUS S* | GREATER S* | TILDE S* | S+ | |
| 2439 ; | |
| 2440 | |
| 2441 simple_selector_sequence | |
| 2442 : [ type_selector | universal ] | |
| 2443 [ HASH | class | attrib | pseudo | negation ]* | |
| 2444 | [ HASH | class | attrib | pseudo | negation ]+ | |
| 2445 ; | |
| 2446 | |
| 2447 type_selector | |
| 2448 : [ namespace_prefix ]? element_name | |
| 2449 ; | |
| 2450 | |
| 2451 namespace_prefix | |
| 2452 : [ IDENT | '*' ]? '|' | |
| 2453 ; | |
| 2454 | |
| 2455 element_name | |
| 2456 : IDENT | |
| 2457 ; | |
| 2458 | |
| 2459 universal | |
| 2460 : [ namespace_prefix ]? '*' | |
| 2461 ; | |
| 2462 | |
| 2463 class | |
| 2464 : '.' IDENT | |
| 2465 ; | |
| 2466 | |
| 2467 attrib | |
| 2468 : '[' S* [ namespace_prefix ]? IDENT S* | |
| 2469 [ [ PREFIXMATCH | | |
| 2470 SUFFIXMATCH | | |
| 2471 SUBSTRINGMATCH | | |
| 2472 '=' | | |
| 2473 INCLUDES | | |
| 2474 DASHMATCH ] S* [ IDENT | STRING ] S* | |
| 2475 ]? ']' | |
| 2476 ; | |
| 2477 | |
| 2478 pseudo | |
| 2479 /* '::' starts a pseudo-element, ':' a pseudo-class */ | |
| 2480 /* Exceptions: :first-line, :first-letter, :before and :after. */ | |
| 2481 /* Note that pseudo-elements are restricted to one per selector and */ | |
| 2482 /* occur only in the last simple_selector_sequence. */ | |
| 2483 : ':' ':'? [ IDENT | functional_pseudo ] | |
| 2484 ; | |
| 2485 | |
| 2486 functional_pseudo | |
| 2487 : FUNCTION S* expression ')' | |
| 2488 ; | |
| 2489 | |
| 2490 expression | |
| 2491 /* In CSS3, the expressions are identifiers, strings, */ | |
| 2492 /* or of the form "an+b" */ | |
| 2493 : [ [ PLUS | '-' | DIMENSION | NUMBER | STRING | IDENT ] S* ]+ | |
| 2494 ; | |
| 2495 | |
| 2496 negation | |
| 2497 : NOT S* negation_arg S* ')' | |
| 2498 ; | |
| 2499 | |
| 2500 negation_arg | |
| 2501 : type_selector | universal | HASH | class | attrib | pseudo | |
| 2502 ;</pre> | |
| 2503 | |
| 2504 | |
| 2505 <h3><a name=lex>10.2. Lexical scanner</a></h3> | |
| 2506 | |
| 2507 <p>The following is the <a name=x3>tokenizer</a>, written in Flex (see | |
| 2508 <a href="#refsFLEX">[FLEX]</a>) notation. The tokenizer is | |
| 2509 case-insensitive.</p> | |
| 2510 | |
| 2511 <p>The two occurrences of "\377" represent the highest character | |
| 2512 number that current versions of Flex can deal with (decimal 255). They | |
| 2513 should be read as "\4177777" (decimal 1114111), which is the highest | |
| 2514 possible code point in Unicode/ISO-10646. <a | |
| 2515 href="#refsUNICODE">[UNICODE]</a></p> | |
| 2516 | |
| 2517 <pre>%option case-insensitive | |
| 2518 | |
| 2519 ident [-]?{nmstart}{nmchar}* | |
| 2520 name {nmchar}+ | |
| 2521 nmstart [_a-z]|{nonascii}|{escape} | |
| 2522 nonascii [^\0-\177] | |
| 2523 unicode \\[0-9a-f]{1,6}(\r\n|[ \n\r\t\f])? | |
| 2524 escape {unicode}|\\[^\n\r\f0-9a-f] | |
| 2525 nmchar [_a-z0-9-]|{nonascii}|{escape} | |
| 2526 num [0-9]+|[0-9]*\.[0-9]+ | |
| 2527 string {string1}|{string2} | |
| 2528 string1 \"([^\n\r\f\\"]|\\{nl}|{nonascii}|{escape})*\" | |
| 2529 string2 \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})*\' | |
| 2530 invalid {invalid1}|{invalid2} | |
| 2531 invalid1 \"([^\n\r\f\\"]|\\{nl}|{nonascii}|{escape})* | |
| 2532 invalid2 \'([^\n\r\f\\']|\\{nl}|{nonascii}|{escape})* | |
| 2533 nl \n|\r\n|\r|\f | |
| 2534 w [ \t\r\n\f]* | |
| 2535 | |
| 2536 %% | |
| 2537 | |
| 2538 [ \t\r\n\f]+ return S; | |
| 2539 | |
| 2540 "~=" return INCLUDES; | |
| 2541 "|=" return DASHMATCH; | |
| 2542 "^=" return PREFIXMATCH; | |
| 2543 "$=" return SUFFIXMATCH; | |
| 2544 "*=" return SUBSTRINGMATCH; | |
| 2545 {ident} return IDENT; | |
| 2546 {string} return STRING; | |
| 2547 {ident}"(" return FUNCTION; | |
| 2548 {num} return NUMBER; | |
| 2549 "#"{name} return HASH; | |
| 2550 {w}"+" return PLUS; | |
| 2551 {w}">" return GREATER; | |
| 2552 {w}"," return COMMA; | |
| 2553 {w}"~" return TILDE; | |
| 2554 ":not(" return NOT; | |
| 2555 @{ident} return ATKEYWORD; | |
| 2556 {invalid} return INVALID; | |
| 2557 {num}% return PERCENTAGE; | |
| 2558 {num}{ident} return DIMENSION; | |
| 2559 "<!--" return CDO; | |
| 2560 "-->" return CDC; | |
| 2561 | |
| 2562 "url("{w}{string}{w}")" return URI; | |
| 2563 "url("{w}([!#$%&*-~]|{nonascii}|{escape})*{w}")" return URI; | |
| 2564 U\+[0-9a-f?]{1,6}(-[0-9a-f]{1,6})? return UNICODE_RANGE; | |
| 2565 | |
| 2566 \/\*[^*]*\*+([^/*][^*]*\*+)*\/ /* ignore comments */ | |
| 2567 | |
| 2568 . return *yytext;</pre> | |
| 2569 | |
| 2570 | |
| 2571 | |
| 2572 <h2><a name=downlevel>11. Namespaces and down-level clients</a></h2> | |
| 2573 | |
| 2574 <p>An important issue is the interaction of CSS selectors with XML | |
| 2575 documents in web clients that were produced prior to this | |
| 2576 document. Unfortunately, due to the fact that namespaces must be | |
| 2577 matched based on the URI which identifies the namespace, not the | |
| 2578 namespace prefix, some mechanism is required to identify namespaces in | |
| 2579 CSS by their URI as well. Without such a mechanism, it is impossible | |
| 2580 to construct a CSS style sheet which will properly match selectors in | |
| 2581 all cases against a random set of XML documents. However, given | |
| 2582 complete knowledge of the XML document to which a style sheet is to be | |
| 2583 applied, and a limited use of namespaces within the XML document, it | |
| 2584 is possible to construct a style sheet in which selectors would match | |
| 2585 elements and attributes correctly.</p> | |
| 2586 | |
| 2587 <p>It should be noted that a down-level CSS client will (if it | |
| 2588 properly conforms to CSS forward compatible parsing rules) ignore all | |
| 2589 <code>@namespace</code> at-rules, as well as all style rules that make | |
| 2590 use of namespace qualified element type or attribute selectors. The | |
| 2591 syntax of delimiting namespace prefixes in CSS was deliberately chosen | |
| 2592 so that down-level CSS clients would ignore the style rules rather | |
| 2593 than possibly match them incorrectly.</p> | |
| 2594 | |
| 2595 <p>The use of default namespaces in CSS makes it possible to write | |
| 2596 element type selectors that will function in both namespace aware CSS | |
| 2597 clients as well as down-level clients. It should be noted that | |
| 2598 down-level clients may incorrectly match selectors against XML | |
| 2599 elements in other namespaces.</p> | |
| 2600 | |
| 2601 <p>The following are scenarios and examples in which it is possible to | |
| 2602 construct style sheets which would function properly in web clients | |
| 2603 that do not implement this proposal.</p> | |
| 2604 | |
| 2605 <ol> | |
| 2606 <li> | |
| 2607 | |
| 2608 <p>The XML document does not use namespaces.</p> | |
| 2609 | |
| 2610 <ul> | |
| 2611 | |
| 2612 <li>In this case, it is obviously not necessary to declare or use | |
| 2613 namespaces in the style sheet. Standard CSS element type and | |
| 2614 attribute selectors will function adequately in a down-level | |
| 2615 client.</li> | |
| 2616 | |
| 2617 <li>In a CSS namespace aware client, the default behavior of | |
| 2618 element selectors matching without regard to namespace will | |
| 2619 function properly against all elements, since no namespaces are | |
| 2620 present. However, the use of specific element type selectors that | |
| 2621 match only elements that have no namespace ("<code>|name</code>") | |
| 2622 will guarantee that selectors will match only XML elements that do | |
| 2623 not have a declared namespace. </li> | |
| 2624 | |
| 2625 </ul> | |
| 2626 | |
| 2627 </li> | |
| 2628 | |
| 2629 <li> | |
| 2630 | |
| 2631 <p>The XML document defines a single, default namespace used | |
| 2632 throughout the document. No namespace prefixes are used in element | |
| 2633 names.</p> | |
| 2634 | |
| 2635 <ul> | |
| 2636 | |
| 2637 <li>In this case, a down-level client will function as if | |
| 2638 namespaces were not used in the XML document at all. Standard CSS | |
| 2639 element type and attribute selectors will match against all | |
| 2640 elements. </li> | |
| 2641 | |
| 2642 </ul> | |
| 2643 | |
| 2644 </li> | |
| 2645 | |
| 2646 <li> | |
| 2647 | |
| 2648 <p>The XML document does <b>not</b> use a default namespace, all | |
| 2649 namespace prefixes used are known to the style sheet author, and | |
| 2650 there is a direct mapping between namespace prefixes and namespace | |
| 2651 URIs. (A given prefix may only be mapped to one namespace URI | |
| 2652 throughout the XML document; there may be multiple prefixes mapped | |
| 2653 to the same URI).</p> | |
| 2654 | |
| 2655 <ul> | |
| 2656 | |
| 2657 <li>In this case, the down-level client will view and match | |
| 2658 element type and attribute selectors based on their fully | |
| 2659 qualified name, not the local part as outlined in the <a | |
| 2660 href="#typenmsp">Type selectors and Namespaces</a> section. CSS | |
| 2661 selectors may be declared using an escaped colon "<code>\:</code>" | |
| 2662 to describe the fully qualified names, e.g. | |
| 2663 "<code>html\:h1</code>" will match | |
| 2664 <code><html:h1></code>. Selectors using the qualified name | |
| 2665 will only match XML elements that use the same prefix. Other | |
| 2666 namespace prefixes used in the XML that are mapped to the same URI | |
| 2667 will not match as expected unless additional CSS style rules are | |
| 2668 declared for them.</li> | |
| 2669 | |
| 2670 <li>Note that selectors declared in this fashion will | |
| 2671 <em>only</em> match in down-level clients. A CSS namespace aware | |
| 2672 client will match element type and attribute selectors based on | |
| 2673 the name's local part. Selectors declared with the fully | |
| 2674 qualified name will not match (unless there is no namespace prefix | |
| 2675 in the fully qualified name).</li> | |
| 2676 | |
| 2677 </ul> | |
| 2678 | |
| 2679 </li> | |
| 2680 | |
| 2681 </ol> | |
| 2682 | |
| 2683 <p>In other scenarios: when the namespace prefixes used in the XML are | |
| 2684 not known in advance by the style sheet author; or a combination of | |
| 2685 elements with no namespace are used in conjunction with elements using | |
| 2686 a default namespace; or the same namespace prefix is mapped to | |
| 2687 <em>different</em> namespace URIs within the same document, or in | |
| 2688 different documents; it is impossible to construct a CSS style sheet | |
| 2689 that will function properly against all elements in those documents, | |
| 2690 unless, the style sheet is written using a namespace URI syntax (as | |
| 2691 outlined in this document or similar) and the document is processed by | |
| 2692 a CSS and XML namespace aware client.</p> | |
| 2693 | |
| 2694 <h2><a name=profiling>12. Profiles</a></h2> | |
| 2695 | |
| 2696 <p>Each specification using Selectors must define the subset of W3C | |
| 2697 Selectors it allows and excludes, and describe the local meaning of | |
| 2698 all the components of that subset.</p> | |
| 2699 | |
| 2700 <p>Non normative examples: | |
| 2701 | |
| 2702 <div class="profile"> | |
| 2703 <table class="tprofile"> | |
| 2704 <tbody> | |
| 2705 <tr> | |
| 2706 <th class="title" colspan=2>Selectors profile</th></tr> | |
| 2707 <tr> | |
| 2708 <th>Specification</th> | |
| 2709 <td>CSS level 1</td></tr> | |
| 2710 <tr> | |
| 2711 <th>Accepts</th> | |
| 2712 <td>type selectors<br>class selectors<br>ID selectors<br>:link, | |
| 2713 :visited and :active pseudo-classes<br>descendant combinator | |
| 2714 <br>::first-line and ::first-letter pseudo-elements</td></tr> | |
| 2715 <tr> | |
| 2716 <th>Excludes</th> | |
| 2717 <td> | |
| 2718 | |
| 2719 <p>universal selector<br>attribute selectors<br>:hover and :focus | |
| 2720 pseudo-classes<br>:target pseudo-class<br>:lang() pseudo-class<br>all UI | |
| 2721 element states pseudo-classes<br>all structural | |
| 2722 pseudo-classes<br>negation pseudo-class<br>all | |
| 2723 UI element fragments pseudo-elements<br>::before and ::after | |
| 2724 pseudo-elements<br>child combinators<br>sibling combinators | |
| 2725 | |
| 2726 <p>namespaces</td></tr> | |
| 2727 <tr> | |
| 2728 <th>Extra constraints</th> | |
| 2729 <td>only one class selector allowed per sequence of simple | |
| 2730 selectors</td></tr></tbody></table><br><br> | |
| 2731 <table class="tprofile"> | |
| 2732 <tbody> | |
| 2733 <tr> | |
| 2734 <th class="title" colspan=2>Selectors profile</th></tr> | |
| 2735 <tr> | |
| 2736 <th>Specification</th> | |
| 2737 <td>CSS level 2</td></tr> | |
| 2738 <tr> | |
| 2739 <th>Accepts</th> | |
| 2740 <td>type selectors<br>universal selector<br>attribute presence and | |
| 2741 values selectors<br>class selectors<br>ID selectors<br>:link, :visited, | |
| 2742 :active, :hover, :focus, :lang() and :first-child pseudo-classes | |
| 2743 <br>descendant combinator<br>child combinator<br>adjacent sibling | |
| 2744 combinator<br>::first-line and ::first-letter pseudo-elements<br>::before | |
| 2745 and ::after pseudo-elements</td></tr> | |
| 2746 <tr> | |
| 2747 <th>Excludes</th> | |
| 2748 <td> | |
| 2749 | |
| 2750 <p>content selectors<br>substring matching attribute | |
| 2751 selectors<br>:target pseudo-classes<br>all UI element | |
| 2752 states pseudo-classes<br>all structural pseudo-classes other | |
| 2753 than :first-child<br>negation pseudo-class<br>all UI element | |
| 2754 fragments pseudo-elements<br>general sibling combinators | |
| 2755 | |
| 2756 <p>namespaces</td></tr> | |
| 2757 <tr> | |
| 2758 <th>Extra constraints</th> | |
| 2759 <td>more than one class selector per sequence of simple selectors (CSS1 | |
| 2760 constraint) allowed</td></tr></tbody></table> | |
| 2761 | |
| 2762 <p>In CSS, selectors express pattern matching rules that determine which style | |
| 2763 rules apply to elements in the document tree. | |
| 2764 | |
| 2765 <p>The following selector (CSS level 2) will <b>match</b> all anchors <code>a</c
ode> | |
| 2766 with attribute <code>name</code> set inside a section 1 header <code>h1</code>: | |
| 2767 <pre>h1 a[name]</pre> | |
| 2768 | |
| 2769 <p>All CSS declarations attached to such a selector are applied to elements | |
| 2770 matching it. </div> | |
| 2771 | |
| 2772 <div class="profile"> | |
| 2773 <table class="tprofile"> | |
| 2774 <tbody> | |
| 2775 <tr> | |
| 2776 <th class="title" colspan=2>Selectors profile</th></tr> | |
| 2777 <tr> | |
| 2778 <th>Specification</th> | |
| 2779 <td>STTS 3</td> | |
| 2780 </tr> | |
| 2781 <tr> | |
| 2782 <th>Accepts</th> | |
| 2783 <td> | |
| 2784 | |
| 2785 <p>type selectors<br>universal selectors<br>attribute selectors<br>class | |
| 2786 selectors<br>ID selectors<br>all structural pseudo-classes<br> | |
| 2787 all combinators | |
| 2788 | |
| 2789 <p>namespaces</td></tr> | |
| 2790 <tr> | |
| 2791 <th>Excludes</th> | |
| 2792 <td>non-accepted pseudo-classes<br>pseudo-elements<br></td></tr> | |
| 2793 <tr> | |
| 2794 <th>Extra constraints</th> | |
| 2795 <td>some selectors and combinators are not allowed in fragment | |
| 2796 descriptions on the right side of STTS declarations.</td></tr></tbody></ta
ble> | |
| 2797 <form> | |
| 2798 <input type="text" name="test1"/> | |
| 2799 <input type="text" name="foo"/> | |
| 2800 <input type="text" name="foo"/> | |
| 2801 <input type="text" name="foo"/> | |
| 2802 <input type="text" name="foo"/> | |
| 2803 <input type="text" name="foo"/> | |
| 2804 <input type="text" name="foo"/> | |
| 2805 <input type="text" name="foo"/> | |
| 2806 <input type="text" name="foo"/> | |
| 2807 <input type="text" name="foo"/> | |
| 2808 <input type="text" name="foo"/> | |
| 2809 <input type="text" name="foo"/> | |
| 2810 <input type="text" name="foo"/> | |
| 2811 <input type="text" name="foo"/> | |
| 2812 <input type="text" name="foo"/> | |
| 2813 <input type="text" name="foo"/> | |
| 2814 <input type="text" name="foo"/> | |
| 2815 <input type="text" name="foo"/> | |
| 2816 <input type="text" name="foo"/> | |
| 2817 <input type="text" name="foo"/> | |
| 2818 <input type="text" name="foo"/> | |
| 2819 <input type="text" name="foo"/> | |
| 2820 <input type="text" name="foo"/> | |
| 2821 <input type="text" name="foo"/> | |
| 2822 <input type="text" name="foo"/> | |
| 2823 </form> | |
| 2824 | |
| 2825 <p>Selectors can be used in STTS 3 in two different | |
| 2826 manners: | |
| 2827 <ol> | |
| 2828 <li>a selection mechanism equivalent to CSS selection mechanism: declarations | |
| 2829 attached to a given selector are applied to elements matching that selector, | |
| 2830 <li>fragment descriptions that appear on the right side of declarations. | |
| 2831 </li></ol></div> | |
| 2832 | |
| 2833 <h2><a name=Conformance></a>13. Conformance and requirements</h2> | |
| 2834 | |
| 2835 <p>This section defines conformance with the present specification only. | |
| 2836 | |
| 2837 <p>The inability of a user agent to implement part of this specification due to | |
| 2838 the limitations of a particular device (e.g., non interactive user agents will | |
| 2839 probably not implement dynamic pseudo-classes because they make no sense without | |
| 2840 interactivity) does not imply non-conformance. | |
| 2841 | |
| 2842 <p>All specifications reusing Selectors must contain a <a | |
| 2843 href="#profiling">Profile</a> listing the | |
| 2844 subset of Selectors it accepts or excludes, and describing the constraints | |
| 2845 it adds to the current specification. | |
| 2846 | |
| 2847 <p>Invalidity is caused by a parsing error, e.g. an unrecognized token or a toke
n | |
| 2848 which is not allowed at the current parsing point. | |
| 2849 | |
| 2850 <p>User agents must observe the rules for handling parsing errors: | |
| 2851 <ul> | |
| 2852 <li>a simple selector containing an undeclared namespace prefix is invalid</li
> | |
| 2853 <li>a selector containing an invalid simple selector, an invalid combinator | |
| 2854 or an invalid token is invalid. </li> | |
| 2855 <li>a group of selectors containing an invalid selector is invalid.</li> | |
| 2856 </ul> | |
| 2857 | |
| 2858 <p class="foo test1 bar">Specifications reusing Selectors must define how to han
dle parsing | |
| 2859 errors. (In the case of CSS, the entire rule in which the selector is | |
| 2860 used is dropped.)</p> | |
| 2861 | |
| 2862 <!-- Apparently all these references are out of date: | |
| 2863 <p>Implementations of this specification must behave as | |
| 2864 "recipients of text data" as defined by <a href="#refsCWWW">[CWWW]</a> | |
| 2865 when parsing selectors and attempting matches. (In particular, | |
| 2866 implementations must assume the data is normalized and must not | |
| 2867 normalize it.) Normative rules for matching strings are defined in | |
| 2868 <a href="#refsCWWW">[CWWW]</a> and <a | |
| 2869 href="#refsUNICODE">[UNICODE]</a> and apply to implementations of this | |
| 2870 specification.</p>--> | |
| 2871 | |
| 2872 <h2><a name=Tests></a>14. Tests</h2> | |
| 2873 | |
| 2874 <p>This specification has <a | |
| 2875 href="http://www.w3.org/Style/CSS/Test/CSS3/Selectors/current/">a test | |
| 2876 suite</a> allowing user agents to verify their basic conformance to | |
| 2877 the specification. This test suite does not pretend to be exhaustive | |
| 2878 and does not cover all possible combined cases of Selectors.</p> | |
| 2879 | |
| 2880 <h2><a name=ACKS></a>15. Acknowledgements</h2> | |
| 2881 | |
| 2882 <p>The CSS working group would like to thank everyone who has sent | |
| 2883 comments on this specification over the years.</p> | |
| 2884 | |
| 2885 <p>The working group would like to extend special thanks to Donna | |
| 2886 McManus, Justin Baker, Joel Sklar, and Molly Ives Brower who perfermed | |
| 2887 the final editorial review.</p> | |
| 2888 | |
| 2889 <h2><a name=references>16. References</a></h2> | |
| 2890 | |
| 2891 <dl class="refs"> | |
| 2892 | |
| 2893 <dt>[CSS1] | |
| 2894 <dd><a name=refsCSS1></a> Bert Bos, Håkon Wium Lie; "<cite>Cascading Sty
le Sheets, level 1</cite>", W3C Recommendation, 17 Dec 1996, revised 11 Jan 1999 | |
| 2895 <dd>(<code><a href="http://www.w3.org/TR/REC-CSS1">http://www.w3.org/TR/REC-CS
S1</a></code>) | |
| 2896 | |
| 2897 <dt>[CSS21] | |
| 2898 <dd><a name=refsCSS21></a> Bert Bos, Tantek Çelik, Ian Hickson, Hå
;kon Wium Lie, editors; "<cite>Cascading Style Sheets, level 2 revision 1</cite>
", W3C Working Draft, 13 June 2005 | |
| 2899 <dd>(<code><a href="http://www.w3.org/TR/CSS21">http://www.w3.org/TR/CSS21</a>
</code>) | |
| 2900 | |
| 2901 <dt>[CWWW] | |
| 2902 <dd><a name=refsCWWW></a> Martin J. Dürst, François Yergeau, Misha
Wolf, Asmus Freytag, Tex Texin, editors; "<cite>Character Model for the World W
ide Web</cite>", W3C Recommendation, 15 February 2005 | |
| 2903 <dd>(<code><a href="http://www.w3.org/TR/charmod/">http://www.w3.org/TR/charmo
d/</a></code>) | |
| 2904 | |
| 2905 <dt>[FLEX] | |
| 2906 <dd><a name="refsFLEX"></a> "<cite>Flex: The Lexical Scanner Generator</cite>"
, Version 2.3.7, ISBN 1882114213 | |
| 2907 | |
| 2908 <dt>[HTML4] | |
| 2909 <dd><a name="refsHTML4"></a> Dave Ragget, Arnaud Le Hors, Ian Jacobs, editors;
"<cite>HTML 4.01 Specification</cite>", W3C Recommendation, 24 December 1999 | |
| 2910 <dd>(<a href="http://www.w3.org/TR/html4/"><code>http://www.w3.org/TR/html4/</
code></a>) | |
| 2911 | |
| 2912 <dt>[MATH] | |
| 2913 <dd><a name="refsMATH"></a> Patrick Ion, Robert Miner, editors; "<cite>Mathema
tical Markup Language (MathML) 1.01</cite>", W3C Recommendation, revision of 7 J
uly 1999 | |
| 2914 <dd>(<code><a href="http://www.w3.org/TR/REC-MathML/">http://www.w3.org/TR/REC
-MathML/</a></code>) | |
| 2915 | |
| 2916 <dt>[RFC3066] | |
| 2917 <dd><a name="refsRFC3066"></a> H. Alvestrand; "<cite>Tags for the Identificati
on of Languages</cite>", Request for Comments 3066, January 2001 | |
| 2918 <dd>(<a href="http://www.ietf.org/rfc/rfc3066.txt"><code>http://www.ietf.org/r
fc/rfc3066.txt</code></a>) | |
| 2919 | |
| 2920 <dt>[STTS] | |
| 2921 <dd><a name=refsSTTS></a> Daniel Glazman; "<cite>Simple Tree Transformation Sh
eets 3</cite>", Electricité de France, submission to the W3C, 11 November
1998 | |
| 2922 <dd>(<code><a href="http://www.w3.org/TR/NOTE-STTS3">http://www.w3.org/TR/NOTE
-STTS3</a></code>) | |
| 2923 | |
| 2924 <dt>[SVG] | |
| 2925 <dd><a name="refsSVG"></a> Jon Ferraiolo, 藤沢 淳, Dean Jack
son, editors; "<cite>Scalable Vector Graphics (SVG) 1.1 Specification</cite>", W
3C Recommendation, 14 January 2003 | |
| 2926 <dd>(<code><a href="http://www.w3.org/TR/SVG/">http://www.w3.org/TR/SVG/</a></
code>) | |
| 2927 | |
| 2928 <dt>[UNICODE]</dt> | |
| 2929 <dd><a name="refsUNICODE"></a> <cite><a | |
| 2930 href="http://www.unicode.org/versions/Unicode4.1.0/">The Unicode Standard, Ve
rsion 4.1</a></cite>, The Unicode Consortium. Boston, MA, Addison-Wesley, March
2005. ISBN 0-321-18578-1, as amended by <a href="http://www.unicode.org/versions
/Unicode4.0.1/">Unicode 4.0.1</a> and <a href="http://www.unicode.org/versions/U
nicode4.1.0/">Unicode 4.1.0</a>. | |
| 2931 <dd>(<code><a href="http://www.unicode.org/versions/">http://www.unicode.org/v
ersions/</a></code>)</dd> | |
| 2932 | |
| 2933 <dt>[XML10] | |
| 2934 <dd><a name="refsXML10"></a> Tim Bray, Jean Paoli, C. M. Sperberg-McQueen, Eve
Maler, François Yergeau, editors; "<cite>Extensible Markup Language (XML
) 1.0 (Third Edition)</cite>", W3C Recommendation, 4 February 2004 | |
| 2935 <dd>(<a href="http://www.w3.org/TR/REC-xml/"><code>http://www.w3.org/TR/REC-xm
l/</code></a>) | |
| 2936 | |
| 2937 <dt>[XMLNAMES] | |
| 2938 <dd><a name="refsXMLNAMES"></a> Tim Bray, Dave Hollander, Andrew Layman, edito
rs; "<cite>Namespaces in XML</cite>", W3C Recommendation, 14 January 1999 | |
| 2939 <dd>(<a href="http://www.w3.org/TR/REC-xml-names/"><code>http://www.w3.org/TR/
REC-xml-names/</code></a>) | |
| 2940 | |
| 2941 <dt>[YACC] | |
| 2942 <dd><a name="refsYACC"></a> S. C. Johnson; "<cite>YACC — Yet another com
piler compiler</cite>", Technical Report, Murray Hill, 1975 | |
| 2943 | |
| 2944 </dl> | |
| 2945 </body> | |
| 2946 </html> | |
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