JavaScript 的倒计时

时间：2024-01-12 11:21:08

一年前，在网上找到的例子，现在已经找不到出处，对不住原作者，请原谅。修改了一下，在刷新页面的情况下，倒计时不重来。

没有任何样式，纯文字倒计时。

<!DOCTYPE html>

<html>

<head lang="en">

    <meta charset="UTF-8">

    <title>倒计时</title>

</head>

<body>

<label id="time"></label>

<script>

    function CountDown() {

        var localtime=sessionStorage.getItem('time');

        if(localtime){

            if (localtime >= 0) {

                hours=Math.floor(localtime/3600);

                minutes = Math.floor((localtime-hours*3600)/ 60);

                seconds = Math.floor((localtime-hours*3600) % 60);

                hours = hours >= 10 ? hours : '0' + hours;

                minutes = minutes >= 10 ? minutes : '0' + minutes;

                seconds = seconds >= 10 ? seconds : '0' + seconds;

                msg = "距离结束还有"+ hours + "时" + minutes + "分" + seconds + "秒";

                document.getElementById('time').innerHTML = msg;

                if (localtime == 5*60) alert('注意，还有5分钟!');

                --localtime;

                sessionStorage.setItem('time',localtime)

            }

            else {

                document.getElementById('time').innerHTML = "时间到，结束!";

            }

        }else{

            var maxtime = 90*60; //一个半小时，按秒计算，自己调整!

            if (maxtime >= 0) {

                hours=Math.floor(maxtime/3600);

                minutes = Math.floor((maxtime-hours*3600)/ 60);

                seconds = Math.floor((maxtime-hours*3600) % 60);

                hours = hours >= 10 ? hours : '0' + hours;

                minutes = minutes >= 10 ? minutes : '0' + minutes;

                seconds = seconds >= 10 ? seconds : '0' + seconds;

                msg = "距离结束还有"+ hours + "时" + minutes + "分" + seconds + "秒";

                document.getElementById('time').innerHTML = msg;

                --maxtime;

                sessionStorage.setItem('time',maxtime)

            }

            else {

                document.getElementById('time').innerHTML = "时间到，结束!";

            }

        }

    }

    timer = setInterval("CountDown()", 1000);

</script>

</body>

</html>

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