JSFiddle - React, Tailwind, and code Playground

HTML

<div id="_time">0:0:0</div>

JavaScript

var s=0;
var m=0;
var h=0;

var myVar = setInterval(function(){myTimer()}, 1);

function myTimer() {
    
    if(m==60){
        h++;
        m=1;
    }
    
    if(s==60){
        m++;
        s=1;
    }
    
    var _time =  h + ':' + m + ':' + s;
    document.getElementById("_time").innerHTML = _time;
    s++;
}