remove-hidden-attribute-subtree.html

<!DOCTYPE html>
<html>
<body>
<ul>
  <li>Item 1</li>
  <li>Item 2</li>
  <li id="item3" hidden>Item 3</li>
</ul>
</div>
<script>
  function go() {
    document.querySelector('#item3').removeAttribute('hidden');
  }
</script>
</body>
</html>

chromium/content/test/data/accessibility/event/remove-hidden-attribute-subtree.html