<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Test: A Web Animations on ::backdrop</title>
<link rel="help" href="https://fullscreen.spec.whatwg.org/#::backdrop-pseudo-element">
<link rel="match" href="backdrop-animate-002-ref.html">
<dialog id="target">Dialog contents</dialog>
<script>
const target = document.getElementById("target");
target.showModal();
target.animate({
  opacity: [0.1, 0.1],
  backgroundColor: ["green", "green"]
}, {
  pseudoElement: "::backdrop",
  duration: Infinity
});
</script>