Updated Chrome Apps codelab from I/O 2013

chrome/common/extensions/docs/templates/articles/app_codelab_basics.html

+<h1 id="create-chrome-app">
+  <span class="h1-step">Step 1:</span>
+  Create and Run a Chrome App
+</h1>
+
+<p>In this step, you will learn:</p>
+
+<ul>
+  <li>The basic building blocks of a Chrome App package, including the manifest file and background scripts.</li>
+  <li>How to install, run, and debug a Chrome App.</li>
+</ul>
+
+<p>
+  <em>Estimated time to complete this step: 10 minutes.</em>
+  <br>
+  To preview what you will complete in this step, <a href="#launch">jump down to the bottom of this page &#8595;</a>.
+</p>
+
+<h2 id="app-components">Get familiar with Chrome App packages</h2>
+
+<p>Chrome Apps are structured similarly to Chrome extensions
+so current extension developers will find this process to be familiar.</p>
+
+<p>A packaged Chrome App contains these components:</p>
+
+<ul>
+  <li>The <strong>manifest</strong> specifies the meta information of your app. 
+    The manifest tells Chrome about your app, how to launch it, and any extra permissions that it requires.</li>
+  <li>The <strong>event page</strong>, also called a <strong>background script</strong>, is 
+    responsible for managing the app life cycle.
+    The background script is where you register listeners for specific app events such as the launching and closing of the app's window.</li>
+  <li>All <strong>code files</strong> must be included in the Chrome App package. 
+    This includes HTML, CSS, JS, and Native Client modules.</li>
+  <li><strong>Assets</strong>, including app icons, should be included in the package as well.</li>
+</ul>
+
+<h3 id="manifest">Create a manifest</h3>
+
+<p>Open your favorite code/text editor and create the following file named <strong>manifest.json</strong>:</p>
+
+<pre data-filename="manifest.json">
+{
+  "manifest_version": 2,
+  "name": "Codelab",
+  "version": "1",
+  "icons": {
+    "128": "icon_128.png"
+  },
+  "permissions": [],
+  "app": {
+    "background": {
+      "scripts": ["background.js"]
+    }
+  },
+  "minimum_chrome_version": "28"
+}
+</pre>
+
+<p>Notice how this manifest describes a background script named <em>background.js</em>. We'll create that file next.</p>
+
+<pre>
+"background": {
+  "scripts": ["<b>background.js</b>"]
+}
+</pre>
+
+<p>We'll also supply you with an app icon later in this step:</p>
+
+<pre>
+"icons": {
+  "128": "<b>icon_128.png</b>"
+},
+</pre>
+
+<!-- <p>For more detailed information about the manifest file, refer to <a href="/apps/manifest">Manifest File Format</a> in the docs.</p>
+ -->
+<h3 id="background-script">Create a background script</h3>
+
+<p>Create the following file and save it as <strong><em>background.js</em></strong>:</p>
+
+<pre data-filename="background.js">
+/**
+ * Listens for the app launching then creates the window
+ *
+ * @see http://developer.chrome.com/apps/app.window.html
+ */
+chrome.app.runtime.onLaunched.addListener(function() {
+  chrome.app.window.create('index.html', {
+    id: 'main',
+    bounds: { width: 620, height: 500 }
+  });
+});
+</pre>
+
+<p>This background script simply waits for the <a href="/apps/app_runtime.html#event-onLaunched">chrome.app.runtime.onLaunched</a> launch event for the application and executes the callback function:</p>
+
+<pre>
+<b>chrome.app.runtime.onLaunched</b>.addListener(function() {
+  //...
+});
+</pre>
+
+<p>When the Chrome App is launched, 
+<a href="/apps/app_window.html#method-create">chrome.app.window.create()</a>
+will create a new window using a basic HTML page (<em>index.html</em>) as the source. We'll create the HTML view in the next step.</p>
+
+<pre>
+<b>chrome.app.window.create</b>('<b>index.html</b>', {
+  id: 'main',
+  bounds: { width: 620, height: 500 }
+});
+</pre>
+
+<p>Background scripts may contain additional listeners, windows, post messages, 
+and launch data &mdash; all of which are used by the event page to manage the app. <!-- For more detailed information about background scripts, refer to <a href="app_lifecycle.html">Chrome App Lifecycle</a> in the docs. --></p>
+
+<h3 id="html-view">Create an HTML view</h3>
+
+<p>Create a simple web page to display a "Hello World" message to the screen and save it as <strong><em>index.html</em></strong>:</p>
+
+<pre data-filename="index.html">
+&lt;!DOCTYPE html&gt;
+&lt;html&gt;
+&lt;head&gt;
+  &lt;meta charset="utf-8"&gt;
+&lt;/head&gt;
+&lt;body&gt;
+  &lt;h1&gt;Hello, let's code!&lt;/h1&gt;
+&lt;/body&gt;
+&lt;/html&gt;
+</pre>
+
+<p>Just like any other web page, within this HTML file you can include 
+additional packaged JavaScript, CSS, or assets.</p>
+
+<h3 id="app-icon">Add an app icon</h3>
+
+<p>Right-click and save this 128x128 image to your project folder as <strong><em>icon_128.png</em></strong>:</p>
+
+<p align="center"><img src="{{static}}/images/app_codelab/icon_128.png" alt="Chrome App icon for this codelab" /></p>
+
+<p>We will use this PNG as our application's icon that users will see in the launch menu. <!-- For more detailed information about app icons, refer to <a href="/apps/manifest/icons">Manifest - Icons</a> in the docs. --></p>
+
+<h3 id="confirm-files">Confirm that you have created all your files</h3>
+
+<p>You should have these 4 files in your project folder now:</p>
+
+<figure>
+  <img src="{{static}}/images/app_codelab/app-tutorial-files.png" alt="File folder screenshot"/>
+</figure>
+
+<h2 id="developer-mode">Install a Chrome App in developer mode</h2>
+
+<p>Use <strong>developer mode</strong> to quickly load and launch your app without having to finalize your app as a distribution package.</p>
+
+<ol>
+  <li>Access <strong>chrome://extensions</strong> from the Chrome omnibox.</li>
+  <li>Check off the <strong>Developer mode</strong> check box.</li>
+</ol>
+
+<figure>
+  <img src="{{static}}/images/app_codelab/enable-developer-mode.gif" alt="Enable developer mode"/>
+</figure>
+
+<ol start="3">
+  <li>Click <strong>Load unpacked extension</strong>.</li>
+  <li>Using the file picker dialog, navigate to your app's project folder and select it to load your app.</li>
+</ol>
+
+<figure>
+  <img src="{{static}}/images/app_codelab/load-unpacked-extensions.gif" alt="Load unpacked extensions"/>
+</figure>
+
+<h2 id="launch">Launch your finished Hello World app</h2>
+
+<p>After loading your project as an unpacked extension, click <strong>Launch</strong> next to your installed app. A new standalone window should open up:</p>
+
+<figure>
+  <img src="{{static}}/images/app_codelab/step1-completed.png" alt="The finished Hello World app after Step 1"/>
+</figure>
+
+<p>Congratulations, you've just created a new Chrome App!</p>
+
+<h2 id="devtools-debug">Debug a Chrome App with Chrome DevTools</h2>
+
+<p>You can use the <a href="/devtools">Chrome Developer Tools</a> to inspect, debug, audit, and test your 
+app just like you do on a regular web page.</p>
+
+<p>After you make changes to your code and reload your app (<b>right-click &gt; Reload App</b>), check the DevTools console for any errors (<b>right-click &gt; Inspect Element</b>).</p>
+
+<figure>
+  <img src="{{static}}/images/app_codelab/inspect-element.png" alt="Inspect Element dialog box"/>
+</figure>
+
+<p>(We'll cover the <strong>Inspect Background Page</strong> option in <a href="app_codelab_alarms.html">Step 3</a> with alarms.)</p>
+
+<p>The DevTools JavaScript console has access to the same APIs available to your app. 
+You can easily test an API call before adding it to your code:</p>
+
+<figure>
+  <img src="{{static}}/images/app_codelab/console-log.png" alt="DevTools console log"/>
+</figure>
+
+<h2 id="recap">Recap APIs referenced in this step</h2>
+
+<p>For more detailed information about some of the APIs introduced in this step, refer to:</p>
+
+<ul>
+  <li>
+    <a href="/apps/manifest" title="Read 'Manifest File Format' in the Chrome developer docs">Manifest File Format</a>
+    <a href="#manifest" class="anchor-link-icon" title="This feature mentioned in 'Create a manifest'">&#8593;</a>
+  </li>
+  <li>
+    <a href="/apps/manifest/icons" title="Read 'Manifest - Icons' in the Chrome developer docs">Manifest - Icons</a>
+    <a href="#app-icon" class="anchor-link-icon" title="This feature mentioned in 'Add an app icon'">&#8593;</a>
+  </li>
+  <li>
+    <a href="app_lifecycle.html" title="Read 'Manifest File Format' in the Chrome developer docs">Chrome App Lifecycle</a>
+    <a href="#background-script" class="anchor-link-icon" title="This feature mentioned in 'Create a background script'">&#8593;</a>
+  </li>
+  <li>
+    <a href="/apps/app_runtime.html#event-onLaunched" title="Read 'chrome.app.runtime.onLaunched' in the Chrome developer docs">chrome.app.runtime.onLaunched</a>
+    <a href="#background-script" class="anchor-link-icon" title="This feature mentioned in 'Create a background script'">&#8593;</a>
+  </li>
+  <li>
+    <a href="/apps/app_window.html#method-create" title="Read 'chrome.app.window.create()' in the Chrome developer docs">chrome.app.window.create()</a>
+    <a href="#background-script" class="anchor-link-icon" title="This feature mentioned in 'Create a background script'">&#8593;</a>
+  </li>
+</ul>
+
+<p>Ready to continue onto the next step? Go to <a href="app_codelab_import_todomvc.html">Step 2 - Import an existing web app &raquo;</a></p>