1<!doctype html>
2<meta charset="utf-8">
3<title>event.timeStamp is initialized using event's relevant global object</title>
4<link rel="help" href="https://dom.spec.whatwg.org/#ref-for-dom-event-timestamp%E2%91%A1">
5<script src="/resources/testharness.js"></script>
6<script src="/resources/testharnessreport.js"></script>
7
8<body>
9<script>
10const t = async_test();
11t.step_timeout(() => {
12  const iframeDelayed = document.createElement("iframe");
13  iframeDelayed.onload = t.step_func_done(() => {
14    // Use eval() to eliminate false-positive test result for WebKit builds before r280256,
15    // which invoked WebIDL accessors in context of lexical (caller) global object.
16    const timeStampExpected = iframeDelayed.contentWindow.eval(`new Event("foo").timeStamp`);
17    const eventDelayed = new iframeDelayed.contentWindow.Event("foo");
18
19    const {get} = Object.getOwnPropertyDescriptor(Event.prototype, "timeStamp");
20    assert_approx_equals(get.call(eventDelayed), timeStampExpected, 5, "via Object.getOwnPropertyDescriptor");
21
22    Object.setPrototypeOf(eventDelayed, Event.prototype);
23    assert_approx_equals(eventDelayed.timeStamp, timeStampExpected, 5, "via Object.setPrototypeOf");
24  });
25  document.body.append(iframeDelayed);
26}, 1000);
27</script>
28