<!doctype html>
<html lang="zh"><!-- TODO(dbeam): dir="ltr"? -->
<!-- Copyright 2015 The Chromium Authors. All rights reserved.
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file. -->
<head>
<!-- 分析：
1、需要先有页面效果
2、倒计时读秒实现
1.定义一个方法实现修改span里的内容
2.定义一个定时器，每秒修改一次
3、跳转。判断标志，为真的时候关闭定时器并跳转到指定页
-->
<style>
p{
text-align : center;
}
p span{
color:red;
}
</style>
</head>
<body>
<!-- 1、页面效果 -->
<p>
<span id = "time">5</span>秒后，跳转到百度
</p>
<script>
var time = 5 ;
<!-- 2、倒计时读秒实现并判断跳转-->
function showTime (){
time--;
if(time<=0){
//clearInterval(id);
location.href = "http://www.baidu.com";
}
var sp = document.getElementById("time");
sp.innerHTML = time ;
}
var id = setInterval(showTime,1000);
</script>
</body>
</html>
