JSFiddle - React, Tailwind, and code Playground

HTML

<div id="countup">
  <p id="days">00</p>
  <p class="timeRefDays"></p>
  <p id="hours">00</p>
  <p class="timeRefHours">:</p>
  <p id="minutes">00</p>
  <p class="timeRefMinutes">:</p>
  <p id="seconds">00</p>
  <p class="timeRefSeconds"></p>
</div>

CSS

#countup p {
display: inline-block;
padding: 0px;
margin:0;
//background: #FFA500;
}

JavaScript

function upTime(countTo) {

if(!countTo) countTo = new Date(); // set null if need

  now = new Date();
  countTo = new Date(countTo);
  difference = (now-countTo);

  days=Math.floor(difference/(60*60*1000*24)*1);
  hours=Math.floor((difference%(60*60*1000*24))/(60*60*1000)*1);
  mins=Math.floor(((difference%(60*60*1000*24))%(60*60*1000))/(60*1000)*1);
  secs=Math.floor((((difference%(60*60*1000*24))%(60*60*1000))%(60*1000))/1000*1);

	if(days>0)
  	$('#days p').val= days + ' d';
  else
  $('#days p').val = '';
  
  $('#hours p').val= hours;
  $('#minutes p').val = mins;
  $('#seconds p').val = secs;

  clearTimeout(upTime.to);
  upTime.to=setTimeout(function(){ upTime(countTo); },1000);
}

 upTime('jan,01,2013,00:00:00'); // ****** Change this line!
 //upTime();