PHP时间戳实现倒计时,JavaScript | 时间戳实现倒计时定时器

PHP时间戳实现倒计时：

$future_date = strtotime('2022-01-01 00:00:00');
$current_date = time();
$diff = $future_date - $current_date;
echo '倒计时: ' . floor($diff / (60 * 60 * 24)) . '天 ' . gmdate('H:i:s', $diff % (60 * 60 * 24));

JavaScript时间戳实现倒计时定时器：

<span id="countdown"></span>

<script>
  var countdownElement = document.getElementById('countdown');
  var futureDate = new Date('2022-01-01 00:00:00').getTime();

  var countdownInterval = setInterval(function() {
    var currentDate = new Date().getTime();
    var diff = futureDate - currentDate;
    var days = Math.floor(diff / (1000 * 60 * 60 * 24));
    var hours = Math.floor((diff % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60));
    var minutes = Math.floor((diff % (1000 * 60 * 60)) / (1000 * 60));
    var seconds = Math.floor((diff % (1000 * 60)) / 1000);

    countdownElement.innerHTML = '倒计时: ' + days + '天 ' + hours + '小时 ' + minutes + '分 ' + seconds + '秒 ';

    if (diff < 0) {
      clearInterval(countdownInterval);
      countdownElement.innerHTML = '时间到了！';
    }
  }, 1000);
</script>