鼠标拖拽效果

    <div id="div3">
    </div>
    <script type="text/javascript">
        
            
        div3.onmousedown= function(e){
            var arr =[];
            arr[0] =[div3.offsetLeft,div3.offsetTop];//记录第一次点击的值;
            var x = e.offsetX;//获取元素鼠标点击坐标
            var y = e.offsetY;//获取元素鼠标点击坐标
            document.onmousemove = function(e){
                div3.style.left=e.clientX -x+"px";//left值
                div3.style.top=e.clientY -y+"px";//top值
                var m =div3.style.left;
                var n =div3.style.top;
                var arr1=[m,n];            
                arr.push(arr1);
            }
            // console.log(arr);
            document.onmouseup= function(){
                document.onmousemove=null;
                document.onmouseup=null;
                var len=arr.length;
                function fh(){
                    len--;
                    if(len<0){
                        clearInterval(t);    
                    }else{
                        div3.style.left=arr[len][0];
                        div3.style.top =arr[len][1];
                        }
                }
                var t=setInterval(fh,10);
            }
         }        
                
    </script>