JavaScript 从左边继续的计数器

Question

我正在尝试创建一个倒计时 24 小时的倒计时计数器，显示天、小时、分钟和秒。问题是我想让它以某种方式保存进度。例如，我将倒计时从现在开始到明天同一时间（24 小时），当用户在 2 小时后进入我的网站时，计数器应该从该用户的 22 小时开始，如果用户关闭网站，然后2 小时后返回，计数器应从该用户的 20 小时开始。我希望它足够清楚。我发现如果可能的话，可以使用 cookie 来完成，但我不确定应该如何完成……如果有人能提供帮助，那就太好了！ :3 到目前为止，这是我的代码： HTML:

<div id="clockdiv">
  <span class="days"></span>
  <span class="hours"></span>
  <span class="minutes"></span>
  <span class="seconds"></span>
</div>

JavaScript

// if there's a cookie with the name myClock, use that value as the deadline
    if(document.cookie && document.cookie.match('myClock')){
// get deadline value from cookie
    var deadline = document.cookie.match(/(^|;)myClock=([^;]+)/)[2];
    }

// otherwise, set a deadline 10 minutes from now and 
// save it in a cookie with that name
    else{
// create deadline 10 minutes from now
        var timeInMinutes = 1380;
        var currentTime = Date.parse(new Date());
        var deadline = new Date(currentTime + timeInMinutes*60*1000);

// store deadline in cookie for future reference
        document.cookie = 'myClock=' + deadline + '; path=/; domain=.optic2n.com';
    }

    function getTimeRemaining(endtime) {
      var t = Date.parse(endtime) - Date.parse(new Date());
      var seconds = Math.floor((t / 1000) % 60);
      var minutes = Math.floor((t / 1000 / 60) % 60);
      var hours = Math.floor((t / (1000 * 60 * 60)) % 24);
      var days = Math.floor(t / (1000 * 60 * 60 * 24));
      return {
        'total': t,
        'days': days,
        'hours': hours,
        'minutes': minutes,
        'seconds': seconds
      };
    }

    function initializeClock(id, endtime) {
      var clock = document.getElementById(id);
      var daysSpan = clock.querySelector('.days');
      var hoursSpan = clock.querySelector('.hours');
      var minutesSpan = clock.querySelector('.minutes');
      var secondsSpan = clock.querySelector('.seconds');

        function updateClock() {
            var t = getTimeRemaining(endtime);

            daysSpan.innerHTML = t.days;
            hoursSpan.innerHTML = ('0' + t.hours).slice(-2);
            minutesSpan.innerHTML = ('0' + t.minutes).slice(-2);
            secondsSpan.innerHTML = ('0' + t.seconds).slice(-2);

            if (t.total <= 0) {
            clearInterval(timeinterval);
            }
        }

        updateClock();
        var timeinterval = setInterval(updateClock, 1000);
    }

    initializeClock('clockdiv', deadline);

提前感谢您的帮助！ :3

此致， Tsvetko Krastev

Answer 1

我可能漏掉了一些东西，但是对于如此简单的事情，您的代码似乎非常复杂。这是我想出的：

HTML:

<div id="clockdiv">
  <span id="d" class="days"></span>days
  <span id="h" class="hours"></span>hrs
  <span id="m" class="minutes"></span>mins
  <span id="s" class="seconds"></span>secs
</div>

Javascript:

var deadline = localStorage.getItem('dl') ? parseInt(localStorage.getItem('dl')) : (Date.now() + 86400000);
var delay = null;
// Good spot to do checks for 24hrs has passed already here

localStorage.setItem('dl',deadline);

function render() {
    if (delay) {
        clearTimeout(delay);
        delay = null;
    }
    var diff = (deadline - Date.now()) / 1000;
    document.getElementById('d').innerHTML = Math.floor(diff / 86400);
    document.getElementById('h').innerHTML = Math.floor(diff / 3600);
    document.getElementById('m').innerHTML = Math.floor((diff / 60) % 60);
    document.getElementById('s').innerHTML = Math.floor(diff % 60);
    delay = setTimeout(render,1000);
}
render();

注意：不会检查 24 小时后要做什么。

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