ldElementCount);
</script>

<script id=sibling>
  content.prepend(document.createTextNode('foo'));
  content.append(document.createTextNode('bar'));

  let d = document.getElementById('para');
  testing.expectEqual('P', d.previousElementSibling.nodeName);
  testing.expectEqual(null, d.nextElementSibling);
</script>

<script id=querySelector>
  testing.expectEqual(null, content.querySelector('foo'));
  testing.expectEqual(null, content.querySelector('#foo'));
  testing.expectEqual('link', content.querySelect