CSS animation-direction

The CSS animation-direction property allows you to specify which direction an animation will be played in.

You can specify whether or not the animation should play in reverse on some or all cycles. When an animation is played in reverse the animation-timing-function is also reversed. For example, when played in reverse, a animation-timing-function of ease-out would appear to be ease-in.

Syntax

animation-direction: [ normal | reverse | alternate | alternate-reverse ] [, [ normal | reverse | alternate | alternate-reverse ] ]*

Possible Values

normal
All iterations of the animation are played as specified.
reverse
Defines that all cycles of the animation are played in the reverse direction from the way they were specified.
alternate
Alternates between the normal direction and reverse direction. Therefore, the odd-numbered cycles are played in the normal direction, and the even-numbered iterations are played in a reverse direction.
alternate-reverse
Same as alternate except in reverse order. Therefore, the odd-numbered cycles are played in reverse direction and the even-numbered cycles are played in normal direction.

In addition, all CSS properties also accept the following CSS-wide keyword values as the sole component of their property value:

initial
Represents the value specified as the property's initial value.
inherit
Represents the computed value of the property on the element's parent.
unset
This value acts as either inherit or initial, depending on whether the property is inherited or not. In other words, it sets all properties to their parent value if they are inheritable or to their initial value if not inheritable.

Basic Property Information

Initial Value
normal
Applies To
All elements, and the :before and :after pseudo elements
Inherited?
No
Media
Visual

Example Code

Basic CSS

animation-direction: alternate-reverse;

Working Example within an HTML Document

<!DOCTYPE html>
<title>Example</title>
<style>
.springy-text {
  color: darkslateblue;
  animation-name: springy-text;
  animation-duration: 1s;
  animation-timing-function: ease-in;
  animation-delay: 0s;
  animation-iteration-count: 6;
  animation-direction: alternate-reverse;
  animation-fill-mode: backwards;
}
@keyframes springy-text {
  0%   {
    letter-spacing:1.2em;
    color: thistle;
  }
  100%   {
    letter-spacing:0.1em;
    color: darkslateblue;
  }
}
</style>
<h3 class="springy-text">Animations!</h3>

Try it with the Online Editor

CSS Specifications

Browser Support

The following table provided by Caniuse.com shows the level of browser support for this feature.

Vendor Prefixes

For maximum browser compatibility many web developers add browser-specific properties by using extensions such as -webkit- for Safari, Google Chrome, and Opera (newer versions), -ms- for Internet Explorer, -moz- for Firefox, -o- for older versions of Opera etc. As with any CSS property, if a browser doesn't support a proprietary extension, it will simply ignore it.

This practice is not recommended by the W3C, however in many cases, the only way you can test a property is to include the CSS extension that is compatible with your browser.

The major browser manufacturers generally strive to adhere to the W3C specifications, and when they support a non-prefixed property, they typically remove the prefixed version. Also, W3C advises vendors to remove their prefixes for properties that reach Candidate Recommendation status.

Many developers use Autoprefixer, which is a postprocessor for CSS. Autoprefixer automatically adds vendor prefixes to your CSS so that you don't need to. It also removes old, unnecessary prefixes from your CSS.

You can also use Autoprefixer with preprocessors such as Less and Sass.