Web Animations Polyfill

<div class="pulse" style="width:150px;">Hello world!</div>
<script>
  var elem = document.querySelector('.pulse');
  var player = document.timeline.play(new Animation(elem, [
      {opacity: "0.5", transform: "scale(0.5)"}, 
      {opacity: "1.0", transform: "scale(1)"}
    ],
    {
      direction: "alternate", duration: 0.5, iterations: Infinity
    }));
</script>

An emulator of the Web Animations specification. Please note that this is still experimental, and that the specification is likely to change in the future.

web-animations-js →