鼠标移动出自己想要的效果

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>js 事件event</title>
    <style>
        div{
            width: 10px;
            height: 10px;
            background: red;
            color: #fff;
            padding: 10px;
            margin-right: 10px;
            position: absolute;   /*这个是关键*/
        }
    </style>
    <script>
       function getpos(ev){
              var scrollTop=document.documentElement.scrollTop||document.body.scrollTop;
              var scrollLeft=document.documentElement.scrollLeft||document.body.scrollLeft;

              return {x:ev.clientX+scrollLeft,y:ev.clientY+scrollTop}
       }


        //效果是样式跟着鼠标的移动而移动
        document.onmousemove=function(ev) {  //鼠标移动
            
            var oDiv=document.getElementsByTagName("div");
            var oEvent=ev||event;
            
            var pos =getpos(oEvent)
           for(var i = oDiv.length-1;i>0;i--){
              oDiv[i].style.left=oDiv[i-1].offsetLeft+"px";
              oDiv[i].style.top=oDiv[i-1].offsetTop+"px";

           }
           oDiv[0].style.left=pos.x+"px";
           oDiv[0].style.top=pos.y+"px";


        }
    </script>
</head>
<body>
    <div>我</div>
    <div>很</div>
    <div>快</div>
    <div>乐</div>
    <div>我</div>
    <div>很</div>
    <div>快</div>
    <div>乐</div>

</body>
</html>