Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The onclose property of the GlobalEventHandlers mixin is an event handler for processing close events sent to a <dialog> element.

The close event fires when the user closes a <dialog>.

Note: To handle the closing of a window, use the beforeunload or unload events.


target.onclose = functionRef;


functionRef is a function name or a function expression. The function receives an Event object as its sole argument.

Only one onclose handler can be assigned to an object at a time. You may prefer to use the EventTarget.addEventListener() method instead, since it's more flexible.


HTML Standard
# handler-onclose

Browser compatibility

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See also