JavaScript 计算器(倒计时)

<p id="demo"></p>
<style>
    p {
      text-align: center;
      font-size: 60px;
    }
</style>
<script>
    // Set the date we're counting down to
    var countDownDate = new Date("Jan 5, 2028 15:37:25").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="demo"
        document.getElementById("demo").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("demo").innerHTML = "EXPIRED";
        }
    }, 1000);
</script>