speculation-rules/prerender/restriction-focus.html

<!DOCTYPE html>
<title>Prerendering documents are not focused</title>
<meta name="timeout" content="long">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/common/utils.js"></script>
<script src="/common/dispatcher/dispatcher.js"></script>
<script src="resources/utils.js"></script>
<body>
<input type="text" id = "prerenderTextField">
<script>

setup(() => assertSpeculationRulesIsSupported());

promise_test(async t => {
  document.getElementById('prerenderTextField').focus();
  assert_true(
      document.hasFocus(),
      'Initial document should have focus.');

  const {exec} = await create_prerendered_page(t);
  const result = await exec(() => {
    const element = document.createElement('input');
    element.setAttribute('type', 'text');
    document.body.appendChild(element);
    element.focus();

    // Post the focus and active states to the initiator page.
    return {
      activeElementUpdated: document.activeElement === element,
      documentHasFocus: document.hasFocus()
    };
  })

  assert_true(result.activeElementUpdated, 'Active element has been updated');
  assert_false(result.documentHasFocus, 'Document should not have focus');
}, 'Prerendering document should update the active element but not have focus');

</script>
</body>