function EventDispatcher(){}
	
	/**
	EventDispatcher.initialize( obj )
	
	オブジェクトobjに、W3C DOM3互換のイベント通知機能を追加します。
	これによりobjは、onLoad等のイベントを発行することができます。
	オブジェクトobjはこれにより、以下のプロパティと関数を装備します。
	obj.addEventListener( イベント名, リスナーオブジェ);
	obj.removeEventListener(　イベント名, リスナーオブジェクト);
	obj.dispatchEvent( Eventオブジェクト);
	
	@param obj	オブジェクト
	*/
	
	
	EventDispatcher.initialize = function(obj){
		//MIX IN following property and function int obj
		//be careful about Name Scape Corrision just for incase
		obj.__ed_eventContainer = new Object();	
		obj.addEventListener = this._addEventListener;
		obj.removeEventListener = this._removeEventListener;
		obj.dispatchEvent = this._dispatchEvent;
	
	}
	
	/*
	CAUTION INTERNAL OBJECT	do not call it directory from EventDispatcher	
	refered from targetObject.addEventListener()
	*/
	
	EventDispatcher._addEventListener = function(eventName, object){
	//CAUTION
	//third param is not implemented yet
	
	//CAUTION:
	//scope of this object is always "TARGET" OBJECT, not EventDispatcher
	if( this.__ed_eventContainer[eventName]==null){
		this.__ed_eventContainer[eventName]=new Array();	
		}
		this.removeEventListener(eventName, object);
		this.__ed_eventContainer[eventName].push(object);	//register object
	}
	
	
	/*
	CAUTION INTERNAL OBJECT	do not call it directory from EventDispatcher
	
	refered from targetObject.removeEventListener()
	*/
	
	EventDispatcher._removeEventListener = function(eventName, object){
		//CAUTION:
		//scope of this object is always "TARGET" OBJECT, not EventDispatcher
		var listener_ar = this.__ed_eventContainer[eventName];
		if(listener_ar == undefined) return;
		
		for(var i=0,ln = listener_ar.length; i<ln;i++){
			var listener = listener_ar[i];
			if(listener==object){
				listener_ar.splice(i,1);
				return;
			}
		}
	}
	
	
	/*
	CAUTION INTERNAL OBJECT	do not call it directory from EventDispatcher
	refered from targetObject.dispatchEvent()
	*/
	
	EventDispatcher._dispatchEvent = function(eventObj){
	//CAUTION:
	//scope of this object is always "TARGET" OBJECT,not EventDispatcher
	if(eventObj.target==null) eventObj.target = this;
	
	var eventName = eventObj.type;
	if( this.__ed_eventContainer[eventName]==null) return;
	
	for(var i=0,ln=this.__ed_eventContainer[eventName].length; i<ln; i++){ 
		var listener = this.__ed_eventContainer[eventName][i];
		if(typeof(listener)=="object"){
			listener[eventName].apply(listener, new Array(eventObj));
			return;
		}else{
			listener(eventObj);
			return;
		}
	}
}