nt.createElement('div');
  el2.id = 'closest';
  el2.className = 'ok';

  testing.expectEqual(el2, el2.closest('#closest'));
  testing.expectEqual(el2, el2.closest('.ok'));
  testing.expectEqual(null, el2.closest('#9000'));
  testing.expectEqual(null, el2.closest('.notok'));

  const sp = document.createElement('span');
  el2.appendChild(sp);
  testing.expectEqual(el2, sp.closest('#closest'));
  testing.expectEqual(null, sp.closest('#9000'));
</script>

<script id=attributes>
  testing.expectEqual(true, con