web_animations_staggered_chaining.html

<!DOCTYPE html>
<meta name="viewport" content="width=device-width, user-scalable=no">
<link rel="stylesheet" type="text/css" href="resources/tablet.css">
<script src="resources/perf_test_helper.js"></script>
<script src="resources/web_animations_api_check.js"></script>

<container id="container"></container>

<script>
var N = PerfTestHelper.getN(1000);
var duration = 1000;

function startAnimation(element) {
  var player = element.animate([
    {opacity: 0},
    {opacity: 1},
  ], duration);
  player.onfinish = function() {
    startAnimation(element);
  }
}

function addElement() {
  var target = document.createElement('target');
  container.appendChild(target);
  startAnimation(target);
}

requestAnimationFrame(function(t) {
  var base = t;
  var i = 0;

  requestAnimationFrame(function staggeredStart(t) {
    elapsed = t - base;
    for (; i < N * Math.min(1, elapsed / duration); i++) {
      addElement();
    }
    if (i < N) {
      requestAnimationFrame(staggeredStart);
    } else {
      PerfTestHelper.signalReady();
    }
  });
});
</script>

chromium/tools/perf/page_sets/tough_animation_cases/web_animations_staggered_chaining.html