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<h1 class="page_title">Events</h1>
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<a>Methods</a>
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<li>
<a href="#method-anchor">methodName</a>
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<li>
<a>Events</a>
<ol>
<li>
<a href="#event-anchor">eventName</a>
</li>
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<a href="#types">Types</a>
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<a href="#id-anchor">id</a>
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For information on how to use experimental APIs, see the <a href="experimental.html">chrome.experimental.* APIs</a> page.
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<!-- STATIC CONTENT PLACEHOLDER -->
<div id="static"><p>
An <code>Event</code> is an object
that allows you to be notified
when something interesting happens.
Here's an example of using the
<code>chrome.tabs.onCreated</code> event
to be notified whenever there's a new tab:
</p>
<pre>chrome.tabs.onCreated.<b>addListener(function(</b>tab<b>) {</b>
appendToLog('tabs.onCreated --'
+ ' window: ' + tab.windowId
+ ' tab: ' + tab.id
+ ' index: ' + tab.index
+ ' url: ' + tab.url);
<b>});</b>
</pre>
<p>
As the example shows,
you register for notification using <code>addListener()</code>.
The argument to <code>addListener()</code>
is always a function that you define to handle the event,
but the parameters to the function depend on
which event you're handling.
Checking the documentation for
<a href="tabs.html#event-onCreated"><code>chrome.tabs.onCreated</code></a>,
you can see that the function has a single parameter:
a <a href="tabs.html#type-Tab">Tab</a> object
that has details about the newly created tab.
</p>
<h2>
Methods
</h2>
<p>
You can invoke the following methods on any <code>Event</code> object:
</p>
<pre>void addListener(function callback(...))
void removeListener(function callback(...))
bool hasListener(function callback(...))
</pre>
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<h2>API reference: chrome.apiname </h2>
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<div class="description">
<p class="todo">Undocumented.</p>
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A description from the json schema def of the function goes here.
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The callback <em>parameter</em> should specify a function
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</p>
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<pre>function(<span>Type param1, Type param2</span>) <span class="subdued">{...}</span>;</pre>
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This function was added in version <b><span></span></b>.
If you require this function, the manifest key
<a href="manifest.html#minimum_chrome_version">minimum_chrome_version</a>
can ensure that your extension won't be run in an earlier browser version.
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<!-- EVENTS -->
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<!-- iterates over all events -->
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<!-- Note: intentionally longer 80 columns -->
<span class="subdued">chrome.bookmarks</span><span>onEvent</span><span class="subdued">.addListener</span>(function(<span>Type param1, Type param2</span>) <span class="subdued">{...}</span>);
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<p class="todo">Undocumented.</p>
<p>
A description from the json schema def of the event goes here.
</p>
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