JSFiddle - React, Tailwind, and code Playground

HTML

<li id="min">0</li>
            <li>:</li>
            <li id="sec">0</li>

CSS

ul li{
    float: left;
    list-style-type: none !important;
    
}

JavaScript

var sec = min = hour = 0;
var clock = 0;
stopWatch = function(){
clearTimeout(clock);
    sec++;
    if (sec >=59){
    sec = 0;
        min++;
    }
    if (min>=59){
    min=0;
        hour++;
    }
    document.getElementById("sec").innerHTML = (sec < 10) ? "0" + sec : sec;
    document.getElementById("min").innerHTML = (min < 10) ? "0" + min : min;
    document.getElementById("hour").innerHTML = (hour < 10) ? "0" + hour : hour;
    clock = setTimeout("stopWatch()",1000);
}
stopWatch();

pause = function(){
clearTimeout(clock);
    return false;
}

play = function(){
    stopWatch();
return false;
}

reset = function(){
    sec = min = hour = 0;
    stopWatch();
return false;
}