chromium/content/test/data/accessibility/event/aria-combo-box-uneditable.html

<!--
@WIN-DENY:*
@WIN-ALLOW:EVENT_OBJECT_VALUECHANGE*
-->
<div aria-controls="listbox1" aria-expanded="false" aria-haspopup="listbox" role="combobox" tabindex="0">Apple</div>
<div role="listbox" id="listbox1"><!-- Options would normally go here --></div>
<script>
  function go() {
    var combo_box = document.querySelector('[role=combobox]');
    combo_box.innerText = 'Orange';
  }
</script>