<title>JS实现倒计时(时、分，秒)</title>
<script>
function ShowCountDown(year,month,day,divname)
{
var now = new Date();
var endDate = new Date(year, month, day);
var leftTime=endDate.getTime()-now.getTime();
var dd = parseInt(leftTime / 1000 / 60 / 60 / 24, 10);//计算剩余的天数
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
dd = checkTime(dd);
hh = checkTime(hh);
mm = checkTime(mm);
ss = checkTime(ss);//小于10的话加0
var cc = document.getElementById(divname);
cc.innerHTML = "距离" + year + "年" + month + "月" + day + "日还有：" + dd + "天" + hh + "小时" + mm + "分" + ss + "秒";
}
function checkTime(i)
{
if (i < 10) {
i = "0" + i;
}
return i;
}
window.setInterval(function(){ShowCountDown(2023,11,11,'countdown');}, 1000);
</script>

<div id="countdown"></div>