chrome/common/extensions/docs/static/index.html

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<h3>What are extensions?</h3>

<p>
Extensions are small software programs that
can modify and enhance the functionality of the Chrome browser.
You write them using web technologies such as
HTML, JavaScript, and CSS.
You can also use the extension system to build
<a href="apps.html">packaged apps</a>,
a downloadable kind of
<a href="http://code.google.com/chrome/apps/index.html">installable web app</a>.
</p>

<p>
<img src="images/index/gmail-small.png" width="91" height="35"
  align="right" style="margin-top:0px; margin-left:0.5em"
  alt="A screenshot of an extension's icon in the browser bar" />
From a user's point of view,
extensions and packaged apps are very different 
because they present very different user interfaces.
Extensions have little to no user interface.
For example, the image to the right shows the icon
that provides the UI for the
<a href="samples.html#gmail">Gmail extension</a>.
</p>

<p>
<img src="images/index/html5app.png" width="200" height="160"
  align="right" style="margin-top:0px; margin-left:0.5em"
  alt="A screenshot of a packaged app that implements a jigsaw puzzle" />
Packaged apps, on the other hand,
look and feel like regular web apps,
with a big-screen design
and rich UI.
The image to the right shows a jigsaw puzzle game
implemented by a packaged app.
</p>

<p>
Both extensions and packaged apps bundle all their files
into a single file that the user downloads and installs.
This bundling means that, unlike ordinary web apps,
extensions and packaged apps don't need to depend
on content from the web.
</p>

<p>
You can distribute your extension or packaged app
by using the
<a href="https://chrome.google.com/webstore/developer/dashboard">Chrome Developer Dashboard</a>
to publish to the
<a href="http://chrome.google.com/webstore">Chrome Web Store</a>.
For more information, see the
<a href="http://code.google.com/chrome/webstore">store developer documentation</a>.
</p>

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<h3>How do I start?</h3>

<p>
<ol>
  <li>
    Follow the <a href="getstarted.html">Getting Started tutorial</a>
    <!-- PENDING: once we have one for packaged apps, change to
      "for _extensions_ or _packaged_apps_" -->
  </li>
  <li>
    Read the
    <a href="overview.html">Overview</a>
  </li>
  <li>
    Keep up-to-date by reading the
    <a href="http://blog.chromium.org/">Chromium blog</a>
  </li>
  <li>
    Subscribe to the
    <a href="http://groups.google.com/a/chromium.org/group/chromium-extensions">chromium-extensions group</a>
    </li>
</ol>
</p>

<h3>Featured videos</h3>

<p>
<a href="http://www.youtube.com/view_play_list?p=CA101D6A85FE9D4B">Technical videos</a> <br />
<a href="http://www.youtube.com/view_play_list?p=38DF05697DE372B1">Developer snapshots</a> (below)
</p>

<p>
<iframe title="YouTube video player" width="300" height="199" src="http://www.youtube.com/embed/wRDPTnY3yO8?rel=0" frameborder="0" allowfullscreen></iframe>
</p>
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