function EventWorker(){
 this.addHandler = EventWorker.addHandler;
}
 
// event worker static method
this.EventWorker.addHandler =
 function (eventRef, func) {
  var eventHandlers = eval(eventRef);
  if (typeof eventHandlers == 'function') { // not first handler
   eval(eventRef + " = function(event) {eventHandlers(event); func(event);}");  
  } else { // first handler
   eval(eventRef + " = func;");
  }
 }