javascript - 如何使用javascript创建分钟倒计时

Question

我有一个像网站一样用 html 编写但离线运行的程序，所以我想在用户登录后添加 35 分钟倒计时，然后当 35 分钟结束时，用户将注销

但我无法获得正确的代码，因为我是 javascript 的新手，但我能够让它计数 60 秒，之后它会通过“注销”提醒用户，但我希望它让用户注销不提醒用户注销

这是html代码

 <div id="counter">1:00</div>

这是javascript代码

    function countdown() {
        var seconds = 60;
        function tick() {
            var counter = document.getElementById("counter");
            seconds--;
            counter.innerHTML = "0:" + (seconds < 10 ? "0" : "") + String(seconds);
            if( seconds > 0 ) {
                setTimeout(tick, 1000);
            } else {
                alert("Game over");
            }
        }
        tick();
    }
    countdown();

Answer 1

    <script>
// Set the date we're counting down to
var countDownDate = new Date("July 12, 2017 09:00:00").getTime();

// Update the count down every 1 second
var x = setInterval(function() {

    // Get todays date and time
    var now = new Date().getTime();

    // Find the distance between now an the count down date
    var distance = countDownDate - now;

    // Time calculations for days, hours, minutes and seconds
    var days = Math.floor(distance / (1000 * 60 * 60 * 24));
    var hours = Math.floor((distance % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
    var minutes = Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
    var seconds = Math.floor((distance % (1000 * 60)) / 1000);

    // Output the result in an element with id="counter"
    document.getElementById("counter").innerHTML = days + "d " + hours + "h "
    + minutes + "m " + seconds + "s ";

    // If the count down is over, write some text 
    if (distance < 0) {
        clearInterval(x);
        document.getElementById("counter").innerHTML = "EXPIRED";
    }
}, 1000);   // time changes in every 1 second
</script> 
<p2>to go</p2>

试一试，根据需要更改日期和时间