Document: transitionrun event

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

The transitionrun event is fired when a CSS transition is first created, i.e. before any transition-delay has begun.

Bubbles Yes
Cancelable No
Interface TransitionEvent
Event handler property ontransitionrun

The original target for this event is the Element that had the transition applied. You can listen for this event on the Document interface to handle it in the capture or bubbling phases. For full details on this event please see the page on HTMLElement: transitionrun.

Examples

This code adds a listener to the transitionrun event:

document.addEventListener('transitionrun', () => {
  console.log('Transition is running but hasn't necessarily started transitioning yet');
});

The same, but using the ontransitionrun property instead of addEventListener():

document.ontransitionrun = () => {
  console.log('Transition started running');
};

See a live example of this event.

Specifications

Specification
CSS Transitions Level 2 (CSS Transitions 2)
# transitionrun

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
transitionrun_event
No
12
53
10
The ontransitionrun attribute is not supported in IE. To listen to this event, use document.addEventListener('transitionrun', function() {});.
?
13.1
12
No
No
53
?
13.4
12
No

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/Document/transitionrun_event