javascript - 每 6 小时倒计时

Question

只是想知道，如果有任何方法或代码，可以为每天每 6 小时设置倒数计时器吗？

例如，我想在这个时间开始倒计时（换句话说，就像每 6 小时一样）：上午 9 点到下午 3 点 下午 3 点到晚上 9 点 下午 9 点到凌晨 3 点 上午 3 点到上午 9 点？

我翻遍了整个网站，找不到这样的倒数计时器..

最好在 HTML 和 javascript/jquery 中。

Answer 1

var timer = {
        started: false,
        timestamp: 0
    },
    trigger = 15;                          //3pm

function timerInit(){
    var hour = new Date().getHours();
    if(!started && hour === trigger){      //When it's 3pm, the timer will start
        startTimer();                      //└─ rewrite the conditional statement 
                                           //   as needed
        //do whatever you want here
        timer.timestamp = +new Date();
        timer.started = true;              //Indicates the timer has been started
    }
    requestAnimationFrame(timerInit);      //setTimeout is not efficient
}
requestAnimationFrame(timerInit);


//This is for when the timer has ended.
function timerEnded(){
    timer.started = false;
}

function startTimer(){
    var d = new Date();
    timePassed = new Date(timer.timestamp + 1000*60*60*6 - d);
    var remaining = {                      //Calculate time difference
        hour: timePassed.getHours(),       // using timestamps
        minute: timePassed.getMinutes(),
        second: timePassed.getSeconds()
    }
    console.log(remaining);
    if(timePassed > 0){
        setTimeout(startTimer, 500);       //Countdown
    }else{
        timerEnded();                      //Ended
    }
}

http://jsfiddle.net/DerekL/kKPcr/7/

Answer 2

您可以使用javascript的本机setInterval方法

例如：

var timer = setInterval(myfunction, 21600) // 21600 seconds == 6 hours