javascript 简单的时钟，从 30 秒开始倒计时，然后执行一个函数
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Simple clock that counts down from 30 seconds and executes a function afterward
提问by thenengah
I have a game that gives a time limit and I need to display a countdown clock for the users and stop the game once the time is up such as 30 seconds. How can I do this in javascript?
我有一个有时间限制的游戏，我需要为用户显示一个倒计时时钟，一旦时间到了，比如 30 秒，就停止游戏。我怎样才能在 javascript 中做到这一点？
回答by casablanca
Use setIntervalto set up a timer. Within this timer, you can update some text in your page and when the time is up, you can call whatever function you want:
使用setInterval设置一个计时器。在此计时器内，您可以更新页面中的一些文本，当时间到时，您可以调用您想要的任何函数：
var timeLeft = 30;
var elem = document.getElementById('some_div');
var timerId = setInterval(countdown, 1000);
function countdown() {
if (timeLeft == 0) {
clearTimeout(timerId);
doSomething();
} else {
elem.innerHTML = timeLeft + ' seconds remaining';
timeLeft--;
}
}<div id="some_div">
</div>回答by zsalzbank
Check out setTimeoutand setInterval:
退房setTimeout和setInterval：
http://www.elated.com/articles/javascript-timers-with-settimeout-and-setinterval/
http://www.elated.com/articles/javascript-timers-with-settimeout-and-setinterval/
回答by praveen-me
You can use setTimeout()function for this like :-
您可以setTimeout()为此使用函数，例如：-
let timeElm = document.getElementById('timeElm');
let timer = function(x) {
if(x === 0) {
return;
}
timeElm.innerHTML = x;
return setTimeout(() => {timer(--x)}, 1000)
}
timer(30);
In this, we use recursion and gave it a setTimeout()of 1000msfor reducing the time.
在这里，我们使用递归并给它一个setTimeout()of1000ms以减少时间。
