JavaScript—倒计时

效果：

代码：

<!doctype html>
<html>
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>倒计时js代码</title>
    <style>
        *
        {
            margin: 0;
            padding: 0;
            list-style: none;
        }
        body
        {
            font-size: 18px;
            text-align: center;
        }
        .time
        {
            height: 30px;
            padding: 200px;
        }
    </style>
</head>
<body>
    <!--倒计时-->
    <div class="time">
        <span id="t_d">00天</span> <span id="t_h">00时</span> <span id="t_m">00分</span> <span
            id="t_s">00秒</span>
    </div>
</body>

<script>
    //倒计时
    function GetRTime() {
        var EndTime = new Date('2017/09/20 00:00:00');
        var NowTime = new Date();
        var t = EndTime.getTime() - NowTime.getTime();
        var d = 0;
        var h = 0;
        var m = 0;
        var s = 0;
        if (t >= 0) {
            d = Math.floor(t / 1000 / 60 / 60 / 24);
            h = Math.floor(t / 1000 / 60 / 60 % 24);
            m = Math.floor(t / 1000 / 60 % 60);
            s = Math.floor(t / 1000 % 60);
        }


        document.getElementById("t_d").innerHTML = d + "天";
        document.getElementById("t_h").innerHTML = h + "时";
        document.getElementById("t_m").innerHTML = m + "分";
        document.getElementById("t_s").innerHTML = s + "秒";
    }
    setInterval(GetRTime, 0);

</script>

</html>

暂停时间clearInterval

<script>
    //倒计时
    function GetRTime() {
        var EndTime = new Date('2017/09/20 00:00:00');
        var NowTime = new Date();
        var t = EndTime.getTime() - NowTime.getTime();
        var d = 0;
        var h = 0;
        var m = 0;
        var s = 0;
        if (t >= 0) {
            d = Math.floor(t / 1000 / 60 / 60 / 24);
            h = Math.floor(t / 1000 / 60 / 60 % 24);
            m = Math.floor(t / 1000 / 60 % 60);
            s = Math.floor(t / 1000 % 60);
        }

        document.getElementById("t_d").innerHTML = d + "天";
        document.getElementById("t_h").innerHTML = h + "时";
        document.getElementById("t_m").innerHTML = m + "分";
        document.getElementById("t_s").innerHTML = s + "秒";
    }
    var timer = setInterval(GetRTime, 0);
    
    function TimeStop() {
        //停止
        clearInterval(timer);
    }
</script>