<!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、需要先有頁面效果
2、倒計時讀秒實現
1.定義一個方法實現修改span裏的內容
2.定義一個定時器，每秒修改一次
3、跳轉。判斷標誌，爲真的時候關閉定時器並跳轉到指定頁
-->
<style>
p{
text-align : center;
}
p span{
color:red;
}
</style>
</head>
<body>
<!-- 1、頁面效果 -->
<p>
<span id = "time">5</span>秒後，跳轉到百度
</p>
<script>
var time = 5 ;
<!-- 2、倒計時讀秒實現並判斷跳轉-->
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>
