JSFiddle - React, Tailwind, and code Playground

HTML

<div id="log"></div>

JavaScript

var ITERATIONS = 1000000;

log.textContent = 'Running...';

setTimeout(function () {

    var count = {good: 0, bad: 0};
    var i, x;
    
    for (i = 0; i < ITERATIONS; i += 1) {
        x = Math.random().toString(16).slice(-6);
        result = x.length === 6 && x.indexOf('.') === -1 ? 'good' : 'bad';
        count[result] += 1;
    }
    
    count.percentBad = count.bad / ITERATIONS * 100 + '%';
    
    log.textContent = JSON.stringify(count);

}, 0);