JS实现倒计时
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>js倒计时</title>
<script src="/jquery.min.js"></script>
<script type="text/javascript">
function countTime() {
//获取当前时间
var date = new Date();
var now = date.getTime();
//设置截止时间
var str = "2020/3/28 00:00:00";
var endDate = new Date(str);
var end = endDate.getTime();
//时间差
var leftTime = end - now;
//定义变量 d,h,m,s保存倒计时的时间
var d, h, m, s;
if (leftTime >= 0) {
d = Math.floor(leftTime / 1000 / 60 / 60 / 24);
h = Math.floor(leftTime / 1000 / 60 / 60 % 24);
m = Math.floor(leftTime / 1000 / 60 % 60);
s = Math.floor(leftTime / 1000 % 60);
}
//将倒计时赋值到div中
document.getElementById("_d").innerHTML = d + "天";
document.getElementById("_h").innerHTML = h + "时";
document.getElementById("_m").innerHTML = m + "分";
document.getElementById("_s").innerHTML = s + "秒";
//递归每秒调用countTime方法，显示动态时间效果
setTimeout(countTime, 1000);
}
</script>
</head>
<body onload="countTime()">
<div>
<span id="_d">00</span>
<span id="_h">00</span>
<span id="_m">00</span>
<span id="_s">00</span>
</div>
</body>
</html>
