JSFiddle - React, Tailwind, and code Playground

by Tan

HTML

<div id="counter"></div>

JavaScript

var START_DATE = new Date("December 1, 2010 20:00:00"); // put in the starting date here
            var INTERVAL = 1; // in seconds
            var INCREMENT = 1; // increase per tick
            var START_VALUE = 4166667; // initial value when it's the start date
            var count = 0;
 
            window.onload = function() {
                var msInterval = INTERVAL * 1000;
                var now = new Date();
                count = parseInt((now - START_DATE)/msInterval) * INCREMENT + START_VALUE;
                document.getElementById('counter').innerHTML = addCommas(count.toString());
                setInterval(incrCount, msInterval);
            }
 
            function incrCount() {
                count += INCREMENT;
                document.getElementById('counter').innerHTML = addCommas(count.toString());
            }
 
            function addCommas(nStr){
                nStr += '';
                x = nStr.split('.');
                x1 = x[0];
                x2 = x.length > 1 ? '.' + x[1] : '';
                var rgx = /(\\d+)(\\d{3})/;
                while (rgx.test(x1)) {
                    x1 = x1.replace(rgx, '$1' + ',' + '$2');
                }
                return x1 + x2;
            }