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 EventHandler 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 onbeforeunload or onunload.


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.


Specification Status Comment
HTML Living Standard
The definition of 'onclose' in that specification.
Living Standard

Browser compatibility

BCD tables only load in the browser

See also