Call a function when the page is about to be unloaded:
<body onbeforeunload="return myFunction()">
Try it Yourself »
The onbeforeunload
event occurs when a document is about to be unloaded.
This event allows you to display a message in a confirmation dialog box to inform the user whether he/she wants to stay or leave the current page.
The default message that appears in the confirmation box, is different in different browsers. However, the standard message is something like "Are you sure you want to leave this page?".
This message cannot be removed, unless you call preventDefault() on the event.
In JavaScript, using the addEventListener() method:
object.addEventListener("beforeunload",
myScript);
Try it Yourself »
Bubbles: | No |
---|---|
Cancelable: | Yes |
Event type: | UiEvent if generated from a user interface, Event otherwise |
HTML tags: | <body> |
DOM Version: | Level 2 Events |
onbeforeunload
is a DOM Level 2 (2001) feature.
It is fully supported in all browsers:
Chrome | Edge | Firefox | Safari | Opera | IE |
Yes | Yes | Yes | Yes | Yes | 9-11 |
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