<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<div id="one" style="color:red ;font-size:10cm; text-align:center;">0</div>
<script>
one=document.getElement("one")
var i=1;
var dt=null;
function stop(){
clearInterval(dt)
}
function star(){
dt=setInterval(function(){
one.innerText=Math.round(Math.random()*100)
},50)
}
</script>
<button onclick="star()">开始</button>
<button onclick="stop()">结束</button>
</body>
</html>
原文：http://www.cnblogs.com/wangxirui/p/6371460.html