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Document: transitionstart event

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

The transitionstart event is fired when a CSS transition has actually started, i.e., after any transition-delay has ended.

The difference is transitionstart and transitionrun is that transitionrun fires when the transition is created (i.e. at the start of any delay) and transitionstart fires when the actual animation has begun (i.e. at the end of any delay).

Bubbles Yes
Cancelable No
Interface TransitionEvent
Event handler property GlobalEventHandlers.ontransitionstart

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: transitionstart.

Examples

This code adds a listener to the transitionstart event:

document.addEventListener('transitionstart', () => {
  console.log('Started transitioning');
});

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

document.ontransitionrun = () => {
  console.log('Started transitioning');
};

See a live example of this event.

Specifications

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
transitionstart_event
No
12
53
10
The ontransitionstart attribute is not supported in IE. To listen to this event, use document.addEventListener('transitionstart', function() {});.
No
13.1
No
No
53
No
13.4
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/transitionstart_event