JSFiddle - React, Tailwind, and code Playground

HTML

<label id=count_label_ms></label>
<br>
<p>
    <input type=button value="stop" />
    <input type=button value="reset" />
    <input type=button value="start" onclick="start()" />
</p>

JavaScript

var countms = 0;

function start() {
    var counterms = setInterval(function () {
        countms = countms + 1;
        var id_label_ms = document.getElementById("count_label_ms");
        id_label_ms.innerHTML = countms / 100 + " s";
    }, 1);
}

function stop() {
    clearInterval(counterms);
}