JavaScript 实现时分秒毫秒倒计时功能

完整代码示例

<!DOCTYPE html>
<html lang="en">
<head>
 <meta charset="UTF-8">
 <title>js时分秒毫秒倒计时</title>
</head>
<body>
<div class="active_time" id="active_time"></div>
<script src="http://code.jquery.com/jquery-2.1.1.min.js"></script>
<script>
 //js部分
 function countTime(value) {
 //获取当前时间
 var date = new Date();
 var now = date.getTime();

 //设置截止时间
 //在pc端浏览器可以这样写
 var endDate = new Date("2019-12-03 00:00:00");
 //移动端必须这样写，因为ios不支持日期中间是-链接，会报错
 //var endDate = new Date("2019/7/22 00:00:00");
 var end = endDate.getTime();
 //时间差
 var differTime = end - now;
 //定义变量,h,m,s保存倒计时的时间
 var h, m, s;
 if (differTime >= 0) {
 h = Math.floor(differTime / 1000 / 60 / 60);
 m = Math.floor(differTime / 1000 / 60 % 60);
 s = Math.floor(differTime / 1000 % 60);
 h = h < 10 ? ("0" + h) : h;
 m = m < 10 ? ("0" + m) : m;
 s = s < 10 ? ("0" + s) : s;
 var timeDom = "倒计时：" + h + "小时" + m + "分" + s + "秒";
 $("#active_time").text(timeDom);
 //递归调用函数所以是延时器不是定时器
 setTimeout(function () {
 countTime(value)
 }, 1000);
 } else {
 var timeDom ="00小时 00分 00秒";
 $("#active_time").text(timeDom);
 }}
 countTime()
</script>
</body>
</html>