<!-- Quirks mode -->
<html>
<head>
<title>ScrollTimeline default source in quirks mode</title>
<link rel="help" href="https://drafts.csswg.org/scroll-animations-1/#dom-scrolltimeline-scrolltimeline">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
/* This is just to make it possible for #body1 to be
"potentially scrollable".
https://drafts.csswg.org/cssom-view/#potentially-scrollable */
html {
overflow: hidden;
}
</style>
</head>
<body id=body1></body>
<script>
test(() => {
try {
assert_equals(document.scrollingElement.id, 'body1');
assert_equals(new ScrollTimeline({}).source, body1);
// Make #body1 "potentially scrollable". This causes the scrollingElement
// of the document to become null.
//
// https://drafts.csswg.org/cssom-view/#dom-document-scrollingelement
body1.style = 'overflow:scroll';
assert_equals(new ScrollTimeline({}).source, null);
} finally {
body1.style = '';
}
}, 'Style of <body> is reflected in source attribute in quirks mode');
</script>
</html>