--- title: window.onunload slug: Web/API/WindowEventHandlers/onunload translation_of: Web/API/WindowEventHandlers/onunload original_slug: Web/API/GlobalEventHandlers/onunload ---

Test Summary

The unload event is raised when the document is unloaded.

Syntax

window.onunload = funcRef;

funcRef is a reference to a function.

Example

<html>
<head>

<title>onunload test</title>

<script type="text/javascript">

window.onunload = unloadPage;

function unloadPage()
{
 alert("unload event detected!");
}
</script>
</head>

<body>
<p>Reload a new page into the browser<br />
 to fire the unload event for this page.</p>
<p>You can also use the back or forward buttons<br />
 to load a new page and fire this event.</p>
</body>
</html>

Notes

Note that using this event handler in your page prevents Firefox 1.5 from caching the page in the in-memory bfcache. See Using Firefox 1.5 caching for details.

Browsers equipped with pop-up window blockers will ignore all window.open() method calls in onunload event handler functions.

Specification

{{ languages( {"zh-cn": "zh-cn/DOM/window.onunload" } ) }}