Initial import of the Chrome Frame codebase. Integration in chrome.gyp coming...

chrome_frame/CFInstall.js

+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview CFInstall.js provides a set of utilities for managing
+ * the Chrome Frame detection and installation process.
+ * @author slightlyoff@google.com (Alex Russell)
+ */
+
+(function(scope) {
+  // bail if we'd be over-writing an existing CFInstall object
+  if (scope['CFInstall']) {
+    return;
+  }
+
+  /** 
+   * returns an item based on DOM ID. Optionally a document may be provided to
+   * specify the scope to search in. If a node is passed, it's returned as-is.
+   * @param {string|Node} id The ID of the node to be located or a node
+   * @param {Node} doc Optional A document to search for id.
+   * @return {Node} 
+   */
+  var byId = function(id, doc) {
+    return (typeof id == 'string') ? (doc || document).getElementById(id) : id;
+  };
+
+  /////////////////////////////////////////////////////////////////////////////
+  // Plugin Detection
+  /////////////////////////////////////////////////////////////////////////////
+  
+  var cachedAvailable;
+
+  /** 
+   * Checks to find out if ChromeFrame is available as a plugin
+   * @return {Boolean} 
+   */
+  var isAvailable = function() {
+    if (typeof cachedAvailable != 'undefined') {
+      return cachedAvailable;
+    }
+
+    cachedAvailable = false;
+
+    // Look for CF in the User Agent before trying more expensive checks
+    var ua = navigator.userAgent.toLowerCase();
+    if (ua.indexOf("chromeframe") >= 0 || ua.indexOf("x-clock") >= 0) {
+      cachedAvailable = true;
+      return cachedAvailable;
+    }
+
+    if (typeof window['ActiveXObject'] != 'undefined') {
+      try {
+        var obj = new ActiveXObject('ChromeTab.ChromeFrame');
+        if (obj) {
+          cachedAvailable = true;
+        }
+      } catch(e) {
+        // squelch
+      }
+    }
+    return cachedAvailable;
+  };
+
+
+  /** @type {boolean} */
+  var cfStyleTagInjected = false;
+
+  /** 
+   * Creates a style sheet in the document which provides default styling for
+   * ChromeFrame instances. Successive calls should have no additive effect.
+   */
+  var injectCFStyleTag = function() {
+    if (cfStyleTagInjected) {
+      // Once and only once
+      return;
+    }
+    try {
+      var rule = '.chromeFrameInstallDefaultStyle {' +
+                    'width: 500px;' +
+                    'height: 400px;' +
+                    'padding: 0;' +
+                    'border: 1px solid #0028c4;' +
+                    'margin: 0;' +
+                  '}';
+      var ss = document.createElement('style');
+      ss.setAttribute('type', 'text/css');
+      if (ss.styleSheet) {
+        ss.styleSheet.cssText = rule;
+      } else {
+        ss.appendChild(document.createTextNode(rule));
+      }
+      var h = document.getElementsByTagName('head')[0];
+      var firstChild = h.firstChild;
+      h.insertBefore(ss, firstChild);
+      cfStyleTagInjected = true;
+    } catch (e) {
+      // squelch
+    }
+  };
+
+
+  /** 
+   * Plucks properties from the passed arguments and sets them on the passed
+   * DOM node
+   * @param {Node} node The node to set properties on
+   * @param {Object} args A map of user-specified properties to set
+   */
+  var setProperties = function(node, args) {
+    injectCFStyleTag();
+
+    var srcNode = byId(args['node']);
+
+    node.id = args['id'] || (srcNode ? srcNode['id'] || getUid(srcNode) : '');
+
+    // TODO(slightlyoff): Opera compat? need to test there
+    var cssText = args['cssText'] || '';
+    node.style.cssText = ' ' + cssText;
+
+    var classText = args['className'] || '';
+    node.className = 'chromeFrameInstallDefaultStyle ' + classText;
+
+    // default if the browser doesn't so we don't show sad-tab
+    var src = args['src'] || 'about:blank';
+
+    node.src = src;
+
+    if (srcNode) {
+      srcNode.parentNode.replaceChild(node, srcNode);
+    }
+  };
+
+  /** 
+   * Creates an iframe.
+   * @param {Object} args A bag of configuration properties, including values
+   *    like 'node', 'cssText', 'className', 'id', 'src', etc.
+   * @return {Node} 
+   */
+  var makeIframe = function(args) {
+    var el = document.createElement('iframe');
+    setProperties(el, args);
+    return el;
+  };
+
+  var CFInstall = {};
+  /** 
+   * Checks to see if Chrome Frame is available, if not, prompts the user to
+   * install. Once installation is begun, a background timer starts,
+   * checkinging for a successful install every 2 seconds. Upon detection of
+   * successful installation, the current page is reloaded, or if a
+   * 'destination' parameter is passed, the page navigates there instead.
+   * @param {Object} args A bag of configuration properties. Respected
+   *    properties are: 'mode', 'url', 'destination', 'node', 'onmissing',
+   *    'preventPrompt', 'oninstall', 'preventInstallDetection', 'cssText', and
+   *    'className'.
+   * @public
+   */
+  CFInstall.check = function(args) {
+    args = args || {};
+
+    // We currently only support CF in IE 
+    // TODO(slightlyoff): Update this should we support other browsers!
+    var ieRe = /MSIE (\S+)/;
+    if (!ieRe.test(navigator.userAgent)) {
+      return;
+    }
+
+
+    // TODO(slightlyoff): Update this URL when a mini-installer page is
+    //   available.
+    var installUrl = '//www.google.com/chromeframe';
+    if (!isAvailable()) {
+      if (args.onmissing) {
+        args.onmissing();
+      }
+
+      args.src = args.url || installUrl;
+      var mode = args.mode || 'inline';
+      var preventPrompt = args.preventPrompt || false;
+
+      if (!preventPrompt) {
+        if (mode == 'inline') {
+          var ifr = makeIframe(args);
+          // TODO(slightlyoff): handle placement more elegantly!
+          if (!ifr.parentNode) {
+            var firstChild = document.body.firstChild;
+            document.body.insertBefore(ifr, firstChild);
+          }
+        } else {
+          window.open(args.src);
+        }
+      }
+
+      if (args.preventInstallDetection) {
+        return;
+      }
+
+      // Begin polling for install success.
+      var installTimer = setInterval(function() {
+          // every 2 seconds, look to see if CF is available, if so, proceed on
+          // to our destination
+          if (isAvailable()) {
+            if (args.oninstall) {
+              args.oninstall();
+            }
+
+            clearInterval(installTimer);
+            // TODO(slightlyoff): add a way to prevent navigation or make it
+            //    contingent on oninstall?
+            window.location = args.destination || window.location;
+          }
+      }, 2000);
+    }
+  };
+
+  CFInstall.isAvailable = isAvailable;
+
+  // expose CFInstall to the external scope. We've already checked to make
+  // sure we're not going to blow existing objects away.
+  scope.CFInstall = CFInstall;
+
+})(this['ChromeFrameInstallScope'] || this);