<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
<h1 id="h">距离倒计时结束还有xx小时xx分钟xx秒</h1>
</body>
</html>
<script>
var h1 = document.getElementById("h");
//获取现在的时间
var now = new Date();
//获取结束的时间
var end = new Date( "2018-08-09 09:34:00" );
//获取时间差（结束时间-开始时间）/1000
var t = ( end.getTime()-now.getTime() )/1000;
//假设值为true时，启动计时器
var flag = true;
function djs(){
if( t < 0 ){
h1.innerHTML = "倒计时结束";
flag = false;
return;
}
//剩余的小时
var h = parseInt( t/3600 );
//剩余的分钟
var m = parseInt( ( t-h*3600 )/60 );
//剩余的秒数
var s = parseInt( t-h*3600-m*60 );
//输出倒计时时间
h1.innerHTML = "距离倒计时结束还有"+h+"小时"+m+"分钟"+s+"秒"
}
djs();
//设置自动倒计时
var time = setInterval( function(){
if( flag ){
t--;
if( t<0 ){
h1.innerHTML = "倒计时结束";
//关闭倒计时
clearInterval( time );
}else{
djs();
}
}
},1000 )
</script>