<!doctype html>
<html>
<head>
  <script>
    window.addEventListener('load', async () => {
      const element = document.getElementById('target');
      element.animate({
        'all': ['initial']
      }, {
        'duration': 500,
        'pseudoElement': '::marker',
      })
      element.hidden = false;
    })
  </script>
</head>
<ul>
  <li id='target' hidden></li>
</ul>
</html>
