JSFiddle - React, Tailwind, and code Playground

HTML

<html>

<body>

<span id = "Timer">00:00:00</span>

</body>

</html>

JavaScript

var clock = function() {
  var mytime = new Date();
  var seconds = mytime.getSeconds();
  var minutes = mytime.getMinutes();
  var hours = mytime.getHours();
  var currentTime = hours + ":" + minutes + ":" + seconds;

  document.getElementById("Timer").firstChild.nodeValue = currentTime;

}
setInterval(clock, 1000);