content/test/data/accessibility/event/description-changed-subtree.html

<!DOCTYPE html>
<html>
<body>
<button id="myButton" aria-describedby="description1">Click Me</button>
<p id="description1">This is description one.</p>
<p id="description2">This is description two.</p>

<script>
  const button = document.getElementById('myButton');

  function go() {
    button.setAttribute('aria-describedby', 'description2');
  }
</script>
</body>
</html>