JSFiddle - React, Tailwind, and code Playground

HTML

<div id="timer">0 Hours 0 Minutes 0 Seconds 0 ms </div>
<input type="button" id="start_btn" value="Start">
<input type="button" id="stop_btn" value="Stop">
<input type="button" id="reset_btn" value="Reset">

JavaScript

var time=new Date(0,0,0,0,0,0,0);
var interId;
var ms=0;
function timer() {
   document.getElementById('timer').innerHTML=time.getHours()+'Hours '+time.getMinutes()+'Minutes '+time.getSeconds()+'Seconds '+time.getMilliseconds()+'ms ';
   time.setMilliseconds(ms++);
}
window.onload=function () {
   document.getElementById('start_btn').onclick=stratTime();
   document.getElementById('stop_btn').onclick=stopTime();
   document.getElementById('reset_btn').onclick=clearTime();
}
function stratTime() {
   alert("start_btn");
   interId=setInterval(timer,1);
}
function stopTime() {
   alert("stop_btn");
   clearInterval(interId);
}
function clearTime() {
   alert("reset_btn");
   time.setTime(0);
}