Animation.persist()

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

The persist() method of the Web Animations API's Animation interface explicitly persists an animation, when it would otherwise be removed due to the browser's Automatically removing filling animations behavior.

Syntax

animation.persist(); 

Parameters

None.

Return value

None.

Examples

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.commitStyles();

  //anim.persist()

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

  console.log(anim.replaceState);
});

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.

Specifications

Specification Status Comment
Web Animations
The definition of 'persist()' in that specification.
Working Draft

Browser compatibility

No compatibility data found. Please contribute data for "api.Animation.persist" (depth: 1) to the MDN compatibility data repository.

See also