实例—完美拖拽

window.onload=function(){
	var oDiv1=document.getElementById(‘div1‘);
	var oDiv2=document.getElementById(‘div2‘);
	
	drag(oDiv1);
	drag(oDiv2);
	function drag(obj)
	{
		obj.onmousedown=function(ev){
			var oEvent=ev||event;
			var disX=oEvent.clientX-obj.offsetLeft;
			var disY=oEvent.clientY-obj.offsetTop;
			obj.onmousemove=function(ev){
				var oEvent=ev||event;
				var left=oEvent.clientX-disX;
				var top=oEvent.clientY-disY;
				
				obj.style.left=left+‘px‘;
				obj.style.top=top+‘px‘;
			};
			obj.onmouseup=function(){
				obj.onmousemove=null;
				obj.onmouseup=null;
				obj.releaseCapture&&obj.releaseCapture();
			};
			obj.setCapture&&obj.setCapture();
			return false;
		};
	}
};

*{margin:0px;padding:0px;}
#div1{width:200px;height:200px;background:red;position:absolute;left:100px;top:100px;}
#div2{width:200px;height:200px;background:green;position:absolute;left:400px;top:100px;}

<div id="div1"></div>
<div id="div2"></div>