<!doctype html>
<body>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
async_test((t) => {
  let onloadIsCalled = false;
  window.addEventListener('load', () => {
    onloadIsCalled = true;
  }, {once: true});
  document.addEventListener('readystatechange', t.step_func(() => {
    if (document.readyState !== 'complete') {
      return;
    }
    const xhr = new XMLHttpRequest();
    xhr.open('GET', 'resources/pass.txt', false /* async */);
    xhr.send();
    assert_false(onloadIsCalled);
    // The load event eventually arrives.
    window.addEventListener('load', t.step_func_done(() => {
    }), {once: 'true'});
  }));
}, 'sync XHR should not fire window.onload synchronously');
</script>
</body>