<html class="reftest-wait">
<title>The default scroll() timeline in quirks mode</title>
<link rel="help" href="https://drafts.csswg.org/scroll-animations-1/#scroll-notation">
<link rel="help" href="https://drafts.csswg.org/css-animations-2/#animation-timeline">
<meta name="assert" content="CSS animation correctly updates values when using the default scroll() timeline">
<link rel="match" href="scroll-timeline-default-ref.html">

<style>
  @keyframes update {
    from { transform: translateY(0px); }
    to { transform: translateY(200px); }
  }

  html {
    min-height: 100%;
    padding-bottom: 100px;
  }

  #box {
    width: 100px;
    height: 100px;
    background-color: green;
    animation: update 1s linear;
    animation-timeline: scroll();
  }

  #covered {
    width: 100px;
    height: 100px;
    background-color: red;
  }

  * {
    margin-top: 0px;
    margin-bottom: 0px;
  }
</style>

<div id="box"></div>
<div id="covered"></div>
<script src="/web-animations/testcommon.js"></script>
<script>
document.documentElement.addEventListener('TestRendered', async () => {
  runTest();
}, { once: true });

async function runTest() {
  const scroller = document.scrollingElement;

  await waitForCompositorReady();

  // Move the scroller to the halfway point. Then advance to the next frame
  // to pick up the new timeline time.
  const maxScroll = scroller.scrollHeight - scroller.clientHeight;
  scroller.scrollTop = 0.5 * maxScroll;

  await waitForNextFrame();
  await waitForNextFrame();

  document.documentElement.classList.remove("reftest-wait");
}

</script>
