How Can I Do A Countdown Timer With Html?

I'm helping my I.T teacher to create easter eggs for some tasks, and I would like to create a countdown timer with html. Explanation: Everytime you enter into a website, the countd

Solution 1:

html code:

<h1>Countdown Clock</h1>
<div id="clockdiv">
  <div>
    <span class="days"></span>
    <div class="text">Days</div>
  </div>
  <div>
    <span class="hours"></span>
    <div class="text">Hours</div>
  </div>
  <div>
    <span class="minutes"></span>
    <div class="text">Minutes</div>
  </div>
  <div>
    <span class="seconds"></span>
    <div class="text">Seconds</div>
  </div>
</div>

css code:

#clockdiv{
    font-family: sans-serif;
    color: #fff;
    display: inline-block;
    font-weight: 100;
    text-align: center;
    font-size: 30px;
}

#clockdiv > div{
    padding: 10px;
    border-radius: 3px;
    background: #00BF96;
    display: inline-block;
}

#clockdiv div > span{
    padding: 15px;
    border-radius: 3px;
    background: #00816A;
    display: inline-block;
}

.text{
    padding-top: 5px;
    font-size: 16px;
}

javascript code:

function getTimeRemaining(endtime) {
  var t = Date.parse("June 31,2017") - 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);
}

var deadline = new Date(Date.parse(new Date()) + 15 * 24 * 60 * 60 * 1000);
initializeClock('clockdiv', deadline);

in the html documnet,include the new files:

<script type="text/javascript" src="assets/js/count.js"></script>

<link rel="stylesheet" type="text/css" href="assets/css/flipclock.css">

hope it works...