JSFiddle - React, Tailwind, and code Playground

HTML

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

JavaScript

var myWorker = null,
    URL = window.URL || (window.webkitURL);

window.URL = URL;

var myWorker = function() {
    var i = 0;
    setInterval(function() {
        i++;
        postMessage(i); // sent data to main app
    }, 500);
}

var workerData = new Blob(['(' + myWorker.toString() + ')()'], {
    type: "text/javascript"
});

function init() {
    if (typeof (Worker) === undefined) {
        alert('No webworker supported');
        return false;
    }

    myWorker = new Worker(window.URL.createObjectURL(workerData));
    myWorker.onmessage = function (e) {
        document.getElementById('counter').innerHTML = e.data;
    };
}

init();