var left, top,width,height,lastX,lastY;
	   var dragable=false;
	   function startDrag(obj,ev){
	    var e =ev||window.event;
        left=obj.offsetLeft;
        top=obj.offsetTop;   
        width=obj.offsetWidth;   
        height=obj.offsetHeight;   
        lastX=e.clientX;//记录上一次的位置   
        lastY=e.clientY;   
        obj.style.filter="alpha(opacity=50)";//拖动的时候设置透明 
		dragable=true;
        return false;   
    }
    function drag(obj,ev){
		if(dragable){
        var e =ev||window.event;
		left +=e.clientX-lastX;  
		top  +=e.clientY-lastY;
        obj.style.left = left +"px";
        obj.style.top =top+"px";
        lastX=e.clientX;//记录上一次的位置   
        lastY=e.clientY;   
		}
        return false;
    }
    function endDrag(obj){
		if(dragable){
		 obj.style.filter="alpha(opacity=100)";
		 dragable=false
		}
		return false;
    } 
	
	function _setBackAsCenter(layer) {
		var odiv = layer;
		var t = odiv.style.display;
		if(odiv.style.display=="block"){
			var top = (document.body.clientHeight)/2+document.body.scrollTop-layer.offsetHeight/2;
			var left = (document.body.clientWidth)/2+document.body.scrollLeft-layer.offsetWidth/2;
			odiv.style.top = top<=0?0:top;
			odiv.style.left = left<=0?0:left;
			odiv.style.display=t;
		}
	}

	function showWindow(obj){
		var win =  typeof(obj)=="string"?document.getElementById(obj):obj;
		if(win){			
			win.style.display="block";
			var frame ;
			if(document.getElementById("shop_block_iframe")){
				frame = document.getElementById("shop_block_iframe");
				frame.display="block";
			}else{
				frame = document.createElement("iframe");
				frame.id="shop_block_iframe";
				frame.style.cssText="position:absolute;border:0px solid red;left:"+win.style.left+"px;top:"+win.style.top+"px;width:"+win.offsetWidth+"px;height:"+win.offsetHeight+"px;z-index:99;";
				frame.style.display="block";
				document.body.appendChild(frame);
			}
				_setBackAsCenter(frame);
				_setBackAsCenter(win);				
			win.focus();
			window.onresize = function(){
			_setBackAsCenter(frame);
			_setBackAsCenter(win);			
			}
			//window.onscroll = function (){
			//_setBackAsCenter(frame);
			//_setBackAsCenter(win);			
			//}			
		}
	}

	function hideWindow(obj){
		var win =  typeof(obj)=="string"?document.getElementById(obj):obj;
		if(win){
			var frame = document.getElementById("shop_block_iframe");
			if(frame){
				frame.style.display="none";
			}
			win.style.display="none";
		}
	}

	//window.onfocus=function(){hideWindow('shop_block')}
	//window.onblur=function(){hideWindow('shop_block')}