JSFiddle - React, Tailwind, and code Playground

HTML

<button id="go">it will be legend...</button>
<div id="output"></div>

JavaScript

var output = document.getElementById('output');
document.getElementById('go').onclick = function() {
    output.textContent += 'wait for it...';
    for (var i=0; i<3000000000; i++) {
        var unused = i; // don't really care
    }
    output.textContent += ' dary!';
};