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

The read-only Animation.replaceState property of the Web Animations API returns the replace state of the animation. This will be active if the animation has been removed, or persisted if Animation.persist() has been invoked on it.


let myReplaceState = Animation.replaceState;


A string that represents the replace state of the anmation. The value can be one of:

  • active: The initial value of the animation's replace state; when the animation has been removed by the browser's Automatically removing filling animations behavior.
  • persisted: The animation has been explicitly persisted by invoking Animation.persist() on it.
  • removed: The animation has been explicitly removed.


In our simple replace indefinite animations demo, you can see the following code:

const divElem = document.querySelector('div');

document.body.addEventListener('mousemove', evt => {
  let anim = divElem.animate(
    { transform: `translate(${ evt.clientX}px, ${evt.clientY}px)` },
    { duration: 500, fill: 'forwards' }



  anim.onremove = function() {
    console.log('Animation removed');


Here we have a <div> element, and an event listener that fires the event handler code whenever the mouse moves. The event handler sets up an animation that animates the <div> element to the position of the mouse pointer. This could result in a huge animations list, which could create a memory leak. For this reason, modern browsers automatically remove overriding forward filling animations.

You can see the replaceState of the animation being logged at the end of the handler. This will be active for each animation by default, or persisted if the persist() call is uncommented.


Specification Status Comment
Web Animations
The definition of 'Animation.replaceState' in that specification.
Working Draft

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Chrome No support No
No support No
Notes Currently Chrome Canary only
Edge No support NoFirefox Full support 75IE No support NoOpera No support NoSafari Full support 13.1WebView Android No support NoChrome Android No support No
No support No
Notes Currently Chrome Canary only
Firefox Android No support NoOpera Android No support NoSafari iOS Full support 13.4Samsung Internet Android No support No


Full support  
Full support
No support  
No support
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
See implementation notes.
See implementation notes.

See also