<!DOCTYPE html>
<div id="foo"></div>
<script src="../../include.js"></script>
<script>
test(() => {
const foo = document.getElementById("foo");
let animation = foo.animate({ opacity: [0, 1] });
println(`Animation's default timeline is the document's timeline: ${animation.timeline === document.timeline}`);
animation = foo.animate({ opacity: [0, 1] }, { timeline: null });
println(`Animation created with null timeline has no timeline: ${animation.timeline === null}`);
});
</script>