JSFiddle - React, Tailwind, and code Playground

HTML

<span id='clock'></span>

JavaScript

var count = 1449744677;
var now = Math.floor(new Date().getTime() / 1000);
count = count - now;
var counter = setInterval(timer, 1000); //1000 will* run it every 1 second
function timer() {
  count = count - 1;
  if(count == -1) {
    clearInterval(counter);
    return;
  }
  var seconds = count % 60;
  var minutes = Math.floor(count / 60);
  var hours = Math.floor(minutes / 60);
  minutes %= 60;
  hours %= 60;
  document.getElementById("clock").innerHTML = hours + "hours " + minutes + "minutes and " + seconds + " seconds left";
}