chromium/content/test/data/accessibility/event/aria-readonly-changed.html

<!--
@UIA-WIN-DENY:*
@UIA-WIN-ALLOW:AriaProperties*
@UIA-WIN-ALLOW:ValueIsReadOnly*
-->
<!DOCTYPE html>
<html>
<body>
  <textarea id="textarea1" aria-label="textarea1">Textarea1</textarea>
  <textarea id="textarea2" aria-label="textarea2">Textarea2</textarea>
  <textarea id="textarea3" aria-label="textarea3" aria-readonly="true">Textarea3</textarea>
  <textarea id="textarea4" aria-label="textarea4" aria-readonly="true">Textarea4</textarea>
  <script>
    function go() {
      // Set aria-readonly default false->false; should not fire an event.
      document.getElementById('textarea1').setAttribute('aria-readonly', false);

      // Set aria-readonly from false->true; should fire an event.
      document.getElementById('textarea2').setAttribute('aria-readonly', true);

      // Set aria-readonly from true->false; should fire an event.
      document.getElementById('textarea3').setAttribute('aria-readonly', false);

      // Set aria-readonly from true->[removed]; should fire an event.
      document.getElementById('textarea4').removeAttribute('aria-readonly');
    }
  </script>
</body>
</html>