add: const masks = Components.interfaces.nsIDOMNSEvent; 
context: function _parseModifiers(aEvent){  var mval = 0;  if (aEvent.shiftKey)    mval |= masks.SHIFT_MASK;  if (aEvent.ctrlKey)    mval |= masks.CONTROL_MASK;  if (aEvent.altKey)    mval |= masks.ALT_MASK;  if (aEvent.metaKey)    mval |= masks.META_MASK;  if (aEvent.accelKey)    mval |= (navigator.platform.indexOf("Mac") >= 0) ? masks.META_MASK :                                                       masks.CONTROL_MASK;  return mval;}
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/8395/bf535ad85eab87424fb3e5621f5166e5eff27c50/EventUtils.js/buggy/testing/mochitest/tests/SimpleTest/EventUtils.js