带有声音的倒数计时器（无按钮）

Question

我正在尝试创建一个简单的倒数计时器，该计时器在完成或达到0时发出蜂鸣声。

 <script>

var countDownDate = new Date("Aug 31, 2018 00:00:00").getTime();
var x = setInterval(function() {
    var now = new Date().getTime();
    var distance = countDownDate - now;

    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);

    document.getElementById("demo").innerHTML = hours + " h"
    + minutes + " m " + seconds + " sec";

    if (distance < 0) {
        clearInterval(x);
        document.getElementById("demo").innerHTML = "Text";
    }
}, 1000);
</script>