chromium/content/test/data/accessibility/event/form-disabled-changed.html

<!DOCTYPE html>
<!--
@MAC-ALLOW:AXEnabled
@WIN-ALLOW:UNAVAILABLE
-->
<form>
  <input type="checkbox">
  <fieldset disabled>
    <input type="radio" disabled>
  </fieldset>
</form>
<script>
  function go() {
    document.querySelector('input[type=checkbox]').disabled = true;
    document.querySelector('input[type=radio]').disabled = false;
    document.querySelector('fieldset').disabled = false;
  }
</script>