倒计时4

<!DOCTYPE html>
<html>

<head>
    <meta charset="UTF-8">
    <title>js简单时分秒倒计时</title>
    <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 = "2018/5/17 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 + "";
        document.getElementById("_h").innerHTML = h + "";
        document.getElementById("_m").innerHTML = m + "";
        document.getElementById("_s").innerHTML = s + "";
        //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>
原文地址:https://www.cnblogs.com/huanghuali/p/8431799.html