fetch/api/basic/keepalive.html

<!doctype html>
<html>
<meta charset="utf-8">
<title>Fetch API: keepalive handling</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/get-host-info.sub.js"></script>
<body>
<script>
const host_info = get_host_info();
promise_test(async (test) => {
  const iframe = document.createElement('iframe');
  iframe.src = host_info.HTTP_REMOTE_ORIGIN +
    '/fetch/api/resources/keepalive-iframe.html';
  document.body.appendChild(iframe);
  const uuid_promise = new Promise((resolve) => {
    window.addEventListener('message', (event) => {
      resolve(event.data);
    });
  });
  await (new Promise((resolve) => iframe.addEventListener('load', resolve)));
  const uuid = await uuid_promise;
  iframe.remove();
  await (new Promise((resolve) => test.step_timeout(resolve, 1000)));
  const response = await fetch(`../resources/stash-take.py?key=${uuid}`);
  const json = await response.json();
  assert_equals(json, 'on');
});
</script>
</body>
</html>