chromium/third_party/blink/web_tests/external/wpt/fenced-frame/resources/ignore-child-fenced-frame-onload-event-inner.html

<!DOCTYPE html>
<title>child frame with delayed onload event</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="utils.js"></script>

<body>
</body>
<script>
  (function () {
    const [element_type, toplevel_loaded_key, result_key] = parseKeylist();

    // Delays the onload event of the iframe for 2 sec.
    if (element_type == "iframe") {
      const img = document.createElement("img");
      img.src = "/common/square.png?pipe=trickle(d2)";
      document.body.appendChild(img);
      return;
    }

    const iframe = document.createElement('iframe');
    iframe.src = generateURL("ignore-child-fenced-frame-onload-event-inner." +
      "html", ["iframe"]);
    document.body.append(iframe);

    let iframe_loaded = false;
    let result = "passed";
    window.onload = async function () {
      const toplevel_loaded = await readValueFromServer(toplevel_loaded_key);
      if (!toplevel_loaded.status || !iframe_loaded)
        result = "failed";
      writeValueToServer(result_key, result);
    }

    iframe.onload = function () {
      iframe_loaded = true;
    }
  })();
</script>

</html>