JSFiddle - React, Tailwind, and code Playground

HTML

<div id="ddd">.</div>

JavaScript

var time = new Date().valueOf();
var kolvo = 0;
var my = {};

my.fun = function() {
    var temp = new Date().valueOf();
    kolvo++;
    document.getElementById("ddd").innerHTML = ((temp-time)/1000).toFixed(3) + ' : ' + kolvo;
};

var StartGame = setInterval(function() {my.fun();}, 20);