JSFiddle - React, Tailwind, and code Playground

HTML

<span id="hours"></span>:<span id="minutes"></span>:<span id="seconds"></span>.<span id="milliseconds"></span>
<br>
<button id="start">Start</button><button id="stop">Stop</button><button id="reset">Reset</button>

JavaScript

$(document).ready(function(){
	$("#hours").html("0");
	$("#minutes").html("0");
	$("#seconds").html("0");
	$("#milliseconds").html("0");

	var time = undefined;

	$("#start").click(function(){
		var hours 			= Number($("#hours").html());
		var minutes 		= Number($("#minutes").html());
		var seconds 		= Number($("#seconds").html());
		var milliseconds 	= Number($("#milliseconds").html());

		time = setInterval(function(){
			milliseconds = Number($("#milliseconds").html());
			if(milliseconds == 1000){
				seconds++;
				if(seconds == 60){
					minutes++;
					if(minutes == 60){
						hours++;
						$("#hours").html(hours);
					}
					$("#minutes").html(minutes);
					seconds = 0;
				}
				$("#seconds").html(seconds);
				milliseconds = 0;
			}
			milliseconds++;
			$("#milliseconds").html(milliseconds);
		},1);
	});

	$("#stop").click(function(){
		if(typeof time != undefined){
			clearInterval(time);
		}
	});

	$("#reset").click(function(){
		if(typeof time != undefined){
			clearInterval(time);
		}
		$("#hours").html("0");
		$("#minutes").html("0");
		$("#seconds").html("0");
		$("#milliseconds").html("0");
	});

});