wpt / css / css-animations / revert-rule-keyframes.html

Status: PASS | Duration: 54ms | Subtests: 2/2 | Open test on wpt.live | wpt.fyi

TestTest SourceSubtests (2/2)

Data from commit:
a50cb89 wpt: run reference-named files which are themselves tests (#836) (2026-09-03)

SubtestStatusMessage
revert-rule in keyframes (width)PASS
revert-rule in keyframes (--x)PASS

/css/css-animations/revert-rule-keyframes.html

<!DOCTYPE html>
<title>CSS Animations: revert-rule in keyframes</title>
<link rel="help" href="https://drafts.csswg.org/css-cascade-5/#revert-rule-keyword">
<link rel="help" href="https://drafts.csswg.org/css-animations/">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  @property --x {
    syntax: "<length>";
    inherits: false;
    initial-value: 0px;
  }
  @keyframes anim {
    from {
      width: revert-rule;
      --x: revert-rule;
    }
    to {
      width: 200px;
      --x: 200px;
    }
  }
  #target {
    width: 100px;
    --x: 100px;
    animation: anim 3600s steps(2, start);
  }
</style>
<div id="target"></div>
<script>
  test(() => {
    assert_true(CSS.supports('color', 'revert-rule'));
    assert_equals(getComputedStyle(target).width, '150px');
  }, 'revert-rule in keyframes (width)');

  test(() => {
    assert_true(CSS.supports('color', 'revert-rule'));
    assert_equals(getComputedStyle(target).getPropertyValue('--x'), '150px');
  }, 'revert-rule in keyframes (--x)');
</script>