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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - MediaQueryList.addListener does not support Object with handleEvent() method"
href="https://bugs.webkit.org/show_bug.cgi?id=156730">156730</a>
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<th>Summary</th>
<td>MediaQueryList.addListener does not support Object with handleEvent() method
</td>
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<th>Classification</th>
<td>Unclassified
</td>
</tr>
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<th>Product</th>
<td>WebKit
</td>
</tr>
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<th>Version</th>
<td>WebKit Nightly Build
</td>
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<th>Hardware</th>
<td>Unspecified
</td>
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<th>OS</th>
<td>Unspecified
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>Normal
</td>
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<th>Priority</th>
<td>P2
</td>
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<th>Component</th>
<td>CSS
</td>
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<th>Assignee</th>
<td>webkit-unassigned@lists.webkit.org
</td>
</tr>
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<th>Reporter</th>
<td>nkronlage@hotmail.com
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<pre>Repro:
var query = matchMedia("(min-width: 400px)");
var listener = {
handleEvent: function() {
document.body.style.background = query.matches ? 'red' : 'blue';
}
}
query.addListener(listener);
listener.handleEvent();
Runnable: <a href="https://jsfiddle.net/j4278otv/">https://jsfiddle.net/j4278otv/</a>
Running this results in the error: "[Error] TypeError: Argument 1 ('listener') to MediaQueryList.addListener must be a function"
The spec (<a href="https://drafts.csswg.org/cssom-view/#mediaquerylist">https://drafts.csswg.org/cssom-view/#mediaquerylist</a>) says the parameter to addListener is an EventListener (<a href="https://dom.spec.whatwg.org/#callbackdef-eventlistener">https://dom.spec.whatwg.org/#callbackdef-eventlistener</a>):
callback interface EventListener {
void handleEvent(Event event);
};
but the implementation only allows functions.
The Node.addEventListener method does support the Object with handleEvent() method: See <a href="https://jsfiddle.net/6nL0epf3/">https://jsfiddle.net/6nL0epf3/</a></pre>
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