<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>JS实现倒计时(时、分，秒)</title>
<script>
function ShowCountDown(divname)
{
var now = new Date();
var year = now.getFullYear();
var month = now.getMonth()+1;
var day = now.getDate(); //获取天数
var hour = parseInt(now.getHours());
var minuttes = now.getMinutes();
var end_hour = 10;
if(hour<10){
end_hour = 10;
}else if(hour<16){
end_hour = 16;
}else if(hour>16){
day = day + 1;
end_hour = 10;
}
var str = year +"-"+ month + "-" + day +" "+end_hour+ ":00:00";
var leftTime = Date.parse(str) - now.getTime();
var hh = parseInt(leftTime / 1000 / 60 / 60 % 24, 10);//计算剩余的小时数
var mm = parseInt(leftTime / 1000 / 60 % 60, 10);//计算剩余的分钟数
var ss = parseInt(leftTime / 1000 % 60, 10);//计算剩余的秒数
hh = checkTime(hh);
mm = checkTime(mm);
ss = checkTime(ss);//小于10的话加0
var cc = document.getElementById(divname);
cc.innerHTML = hh + ":" + mm + ":" + ss + "";
}
function checkTime(i)
{
if (i < 10) {
i = "0" + i;
}
return i;
}
window.setInterval(function(){ShowCountDown('countdown');}, 1000);
//window.setTimeout(function(){ShowCountDown('countdown');}, 1000);
</script>
</head>
<body>
<div id="countdown"></div>
</body>
</html>