addEvent.js

var addEvent;
if('addEventListener' in window){
  addEvent = function(elm, eventType, func){
    elm.addEventListener(eventType, func, false);
  };
}else if('attachEvent' in window){ // IE
  addEvent = function(elm, eventType, func){
    elm.attachEvent('on'+eventType, function(){ func.apply(elm); });
  };
}