function addEvent(oTarget, sType, fpDest) {
  var oOldEvent = oTarget[sType];
  if (typeof oOldEvent != "function") {
    oTarget[sType] = fpDest;
  } else {
    oTarget[sType] = function(e) {
      oOldEvent(e);
      fpDest(e);
    }
  }
}