javascript - 每 3 天倒数计时器

Question

我有点困惑。我需要得到该月的第一天应该开始计算 3 天。到到期重新开始时。

var today = new Date(),
    end = new Date( today.getFullYear(), today.getMonth(), today.getDate() + 3 );

var timer = setInterval(function() {
  var differenceTime, dd, hh, mm, ss, str;

  if ( ( new Date().getDate() == end.getDate() ) || ( new Date().getDate() == 1 ) ) {
    end = new
  } else {
    differenceTime = end - new Date();

    dd = parseInt(differenceTime / (1000 * 60 * 60 * 24));
    hh = parseInt(differenceTime / (60 * 60 * 1000)) % 24;
    mm = parseInt(differenceTime / (1000 * 60)) % 60;
    ss = parseInt(differenceTime / 1000) % 60;

    document.querySelector('.days').innerHTML = format(dd);
    document.querySelector('.hours').innerHTML = format(hh);
    document.querySelector('.minutes').innerHTML = format(mm);
    document.querySelector('.seconds').innerHTML = format(ss);
  }
}, 1000);

function format(num) {
  return (9 < num) ? num : "0" + num;
};

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

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

帮助创造正确的条件。

Answer 1

我尝试尽可能多地重用您的代码。如果我正确理解你的问题，这应该可以解决问题。如果您使用moment.js，您可能会得到一些更清晰的代码，特别是在格式化文本和计算日期之间的差异时。

请记住，该检查并不完全准确，因为它比较的日期最多为秒。

var numberOfDays = 3;
var today = new Date();
var start = getNextStartDate(today);
var end = getNextEndDate(today);

var timer = setInterval(function() {
  var differenceTime, dd, hh, mm, ss, str;
  var now = new Date();
  if (now >= end) {
    start = getNextStartDate(now);
    end = getNextEndDate(now);
  } else {
    differenceTime = end - now;

    dd = parseInt(differenceTime / (1000 * 60 * 60 * 24));
    hh = parseInt(differenceTime / (60 * 60 * 1000)) % 24;
    mm = parseInt(differenceTime / (1000 * 60)) % 60;
    ss = parseInt(differenceTime / 1000) % 60;

    document.querySelector('.days').innerHTML = format(dd);
    document.querySelector('.hours').innerHTML = format(hh);
    document.querySelector('.minutes').innerHTML = format(mm);
    document.querySelector('.seconds').innerHTML = format(ss);
  }
}, 1000);

function getNextEndDate(fromDate) {
  return new Date(fromDate.getFullYear(), fromDate.getMonth(), fromDate.getDate() + numberOfDays);
}

function getNextStartDate(currentDate) {
  var currentDay = currentDate.getDate();
  var index = Math.ceil(currentDay / 3);
  var nextStartDay = 1 + numberOfDays * index
  return new Date(currentDate.getFullYear(), currentDate.getMonth(), nextStartDay);
}

function format(num) {
  return (9 < num) ? num : "0" + num;
};

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

还有一个jsfiddle如果你愿意的话