基于JavaScript实现自动更新倒计时效果

代码示例

<!DOCTYPE html>
<html>
 <head>
 <title>example.html</title>

 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
 <meta http-equiv="description" content="this is my page">
 <meta http-equiv="content-type" content="text/html; charset=UTF-8">

 <!--<link rel="stylesheet" type="text/css" href="./styles.css">-->
 <script>

 //定义计时器，每隔1秒钟调用timer函数
 var timerCount= window.setTimeout("timer()",1000);
 function timer(){
 var date=new Date("2017","1","1","0","0","0");
 var deadlineTime=date.getTime();
 var nowDate=new Date();
 var nowTime=nowDate.getTime();
 var distTime=deadlineTime-nowTime;
 //判断是否到达时间期限
 if(distTime>0){
 var d=Math.floor(distTime/1000/3600/24);
 var h=Math.floor(distTime/1000/3600%24);
 var m=Math.floor(distTime/1000/60%60);
 var s=Math.floor(distTime/1000%60);
 var str="距离2017年元旦还有"+d+"天"+h+"时"+m+"分"+s+"秒";
 document.getElementById("timeout").innerHTML=str;
 timerCount= window.setTimeout("timer()",1000); 
 }
 else{
 //到达时间期限的时候清楚计时器；
 window.clearTimeout(timerCount);
 alert("时间已到");
 }

 }
 </script>
 </head>

 <body>
 <p id="timeout"> </p>

</html>