palemoon-dev/platform/dom/xul/test/test_bug1290965.xul

<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/" type="text/css"?>
<window xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul" xmlns:html="http://www.w3.org/1999/xhtml" xmlns:h="http://www.w3.org/1999/xhtml">
  <script type="application/javascript"
          src="chrome://mochikit/content/tests/SimpleTest/SimpleTest.js" />
  <toolbarbutton oncommand="++countera;" id="a">A</toolbarbutton>
  <toolbarbutton oncommand="++counterb;" id="b">B</toolbarbutton>
  <script type="text/javascript">
  <![CDATA[
    let aEl = document.getElementById('a');
    let bEl = document.getElementById('b');
    let countera = 0;
    let counterb = 0;

    aEl.addEventListener('click', function (aEvent) {
      aEvent.preventDefault();
      let cmdEvent = document.createEvent("xulcommandevent");
      cmdEvent.initCommandEvent("command", true, true, window, 0,
                                aEvent.ctrlKey, aEvent.altKey, aEvent.shiftKey,
                                aEvent.metaKey, null);
      aEvent.currentTarget.dispatchEvent(cmdEvent);
    });

    bEl.addEventListener('click', function (aEvent) {
      let cmdEvent = document.createEvent("xulcommandevent");
      cmdEvent.initCommandEvent("command", true, true, window, 0,
                                aEvent.ctrlKey, aEvent.altKey, aEvent.shiftKey,
                                aEvent.metaKey, null);
      aEvent.currentTarget.dispatchEvent(cmdEvent);
    });

    bEl.click();
    aEl.click();

    is(countera, 1, "Counter should be one as event fires once");
    is(counterb, 2, "Counter should be two as event fires twice");
  ]]>
  </script>
</window>