<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Cascade: 'revert' keyword in transition</title>
<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
<link rel="author" title="Mozilla" href="https://mozilla.org">
<link rel="help" href="https://drafts.csswg.org/css-cascade/#default">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
html, body { margin: 0 }
h1 {
  margin: 0;
  transition: margin 10s;
  transition-delay: -5s; /* So we can expect it to be half-way the transition when toggling the property */
}
</style>
<h1>This is a header that should get some margin</h1>
<script>
test(function() {
  const el = document.querySelector("h1");
  const cs = getComputedStyle(el);
  assert_equals(cs.marginTop, "0px", "Margin before transition");
  el.style.margin = "revert";
  const midTransition = cs.marginTop;
  assert_not_equals(midTransition, "0px", "Margin mid transition");
  el.style.transition = "none";
  assert_not_equals(cs.marginTop, midTransition, "Default margin");
}, "revert works with transitions");
</script>
