<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<style>
#pbox{
width: 100%;
height:100%;
}
#box{
width: 200px;
height: 200px;
background:red;
position: absolute;
}
</style>
</head>
<body>
<input type="button" id="btn" value="随机生成">
<div id="pbox">
<div id="box">
</div>
</div>
</body>
<script>
var btn=document.getElementById("btn");//获取按钮
var box=document.getElementById("box");//获取box
var pbox=document.getElementById("pbox");//获取pbox
var arr=[‘#fff143‘,‘#ff7500‘,‘#a3d900‘,‘#eedeb0‘,‘#ae7000‘,‘#b35c44‘,‘#392f41‘,‘#ff461f‘,‘#44cef6‘,‘#edd1db‘,‘#003371‘];//随机颜色
//给btn注册点击事件ain
btn.onclick=function(){
pbox.innerHTML="";//清空pbo
for(var i=0;i<=10;i++){
var newTip =box.cloneNode(true);
pbox.appendChild(newTip);
var left=parseInt(Math.random()*(900-100+1) + 100);//随机生成左边距
var top=parseInt(Math.random()*(500-100+1) + 100);//随机生成上边距
var bg=Math.floor((Math.random()*arr.length));//生成数组随机数获得随机数组下标
box.style.background=arr[bg];//设置颜色
box.style.top=top+"px";//设置上边距
box.style.left=left+"px";//设置左边距
}
var c=pbox.children;
for(var i=0;i< c.length;i++){
c[i].onmousedown=function (e) {
// alert(this.offsetLeft);
var spacex=e.pageX-this.offsetLeft;
var spacey=e.pageY-this.offsetTop;
this.onmousemove=function (e) {
this.style.left=e.pageX-spacex+"px";
this.style.top=e.pageY-spacey+"px";
}
};
c[i].onmouseup=function () {
this.onmousemove=null;
}
}
}
</script>
</html>
原文：http://www.cnblogs.com/zhousen34/p/7492864.html