Direction

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The direction property of the Web Animations API represents the direction of the animation's playback along its timeline and its behavior after completing each iteration.

Note: Element.animate(), KeyframeEffectReadOnly.KeyframeEffectReadOnly(), and KeyframeEffect.KeyframeEffect() all accept an object of timing properties including direction. The value of direction corresponds directly to AnimationEffectTimingReadOnly.direction in timing objects returned by AnimationEffectReadOnly, KeyframeEffectReadOnly, and KeyframeEffect.

Syntax

// Cause the animation to alternate running forwards and backwards on each loop
var timingProperties = {
  direction: "alternate"
}

Value

A DOMString representing the direction of the animation's playback. It can take one of the following values (defaults to normal):

normal
The animation runs forwards, from beginning to end, in the way we experience the flow of time.
reverse
The animation runs backwards, or "rewinds."
alternate
The animation switches direction after each iteration, going from forwards to backwards then back again every two iterations.
alternate-reverse
The reverse of the above: the animation switches direction after each iteration, going from backwards to forwards then back again every two iterations.

Examples

In the Forgotten Key example, Alice waves her arm up and down by passing her an alternate value for her direction property:

// Get Alice's arm, and wave it up and down
document.getElementById("alice_arm").animate([ 
  { transform: 'rotate(10deg)' }, 
  { transform: 'rotate(-40deg)' }
], {
  easing: 'steps(2, end)',
  iterations: Infinity,
  direction: 'alternate',
  duration: 600
});

Specifications

Specification Status Comment
Web Animations
The definition of 'direction' in that specification.
Working Draft Editor's draft.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support (Yes) 48 (48) No support (Yes) No support
Feature Android Android Webview Chrome for Android Firefox Mobile (Gecko) Firefox OS IE Mobile Opera Mobile Safari Mobile
Basic support ? ? ? ? ? No support No support No support

See also