chromium/third_party/blink/web_tests/external/wpt/fenced-frame/resources/window-navigation-204-inner.html

<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="utils.js"></script>
<title>Fenced frame content to report the value of window.navigation</title>

<body>
<script>
function init() {
  // This file is meant to be navigated to from a <fencedframe> element. It
  // reports back to the page hosting the <fencedframe> after manual timeout
  // indicating that the 204 navigation succeeds without navigating away.
  location.href = "response-204.py";

  step_timeout(function() {
    const [window_data_key] = parseKeylist();
    writeValueToServer(window_data_key, "still in page");
  }, 1000);
}

init();
</script>
</body>