onunload (HTML attribute)

Depr. Version
Browser support (more…)
IE5.5+ FF1+ SA1.3+ OP9.2+
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The onunload event is used to trigger an action once a web page has unloaded (or the browser window has been closed)—effectively, the point at which the visitor to that page has navigated away by following a link, submitting a form, or using some other mechanism that causes a new page to be loaded in its place.

It may also be used in the context of framesets to indicate that the child frame elements have unloaded or been replaced with new documents.


When used as an inline attribute, onunload is most frequently applied to the body element, as shown below:

<body onunload="sayGoodbye();">


This attribute has no fixed value. It’s up to the author to decide on the scripting that’s included here, be that a call to one or more defined functions, or a simple alert() statement.


Internet Explorer Firefox Safari Opera
5.5 6.0 7.0 1.0 1.5 2.0 1.3 2.0 3.0 9.2 9.5
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Every browser listed supports this attribute. However, inline event handlers such as this should be avoided. In the same way that inline CSS styles are frowned upon but externally defined CSS styles are considered good practice, inline event handlers should be stripped out and replaced with events attached unobtrusively through the DOM.

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