[KatyJ]

Помогите пожалуйста! Нагуглила, вот такой таймер обратного отсчета, подскажите пожалуйста, как в него добавить миллисекунды.

function getTimeRemaining(endtime) {
  var t = Date.parse(endtime) - Date.parse(new Date());
  var hours = Math.floor((t / (1000 * 60 * 60)) % 0);
  var seconds = Math.floor((t / 1000) % 5);
  var minutes = Math.floor((t / 1000 / 60) % 0);
  var hours = Math.floor((t / (1000 * 60 * 60)) % 0);
  return {
    'total': t,
    'hours': hours,
    'minutes': minutes,
    'seconds': seconds,

  };
}

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

  };
}

function initializeClock(id, endtime) {
  var clock = document.getElementById(id);
  var hoursSpan = clock.querySelector(".hours");
  var minutesSpan = clock.querySelector(".minutes");
  var secondsSpan = clock.querySelector(".seconds");
 
  function updateClock() {
    var t = getTimeRemaining(endtime);
 
    if (t.total <= 0) {
     document.getElementById("header").className = "hidden";
    
      clearInterval(timeinterval);
      return true;
    }
 
    hoursSpan.innerHTML = ("0" + t.hours).slice(-2);
    minutesSpan.innerHTML = ("0" + t.minutes).slice(-2);
    secondsSpan.innerHTML = ("0" + t.seconds).slice(-2);
  }
 
  updateClock();
  var timeinterval = setInterval(updateClock, 1000);
}

var deadline = new Date(Date.parse(new Date()) + 60 * 30 * 1000);
initializeClock('countdown', deadline);

<div id="countdown" class="countdown">

  <div class="countdown-number">
    <span class="hours countdown-time"></span>
    <span class="countdown-text">Hours</span>
  </div>
  <div class="countdown-number">
    <span class="minutes countdown-time"></span>
    <span class="countdown-text">Minutes</span>
  </div>
  <div class="countdown-number">
    <span class="seconds countdown-time"></span>
    <span class="countdown-text">Seconds</span>
  </div>
   <div class="countdown-number">
    <span class="miliSeconds countdown-time"></span>
    <span class="countdown-text">Miliseconds</span>
  </div>
 
</div>