chromium/content/test/data/accessibility/event/value-value-changed.html

<!--
@WIN-DENY:EVENT_OBJECT_FOCUS*
@UIA-WIN-DENY:AutomationFocusChanged*
-->
<!DOCTYPE html>
<input id="value" type="text" value="something">
<script>
  var go_passes = [
    () => document.querySelector('#value').setAttribute('value', 'new thing'),
    () => document.querySelector('#value').removeAttribute('value'),
  ];

  var current_pass = 0;
  function go() {
    go_passes[current_pass++].call();
    return current_pass < go_passes.length;
  }
</script>