JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>
  
</body>
</html>

CSS

p{
  width: 50px;
  height: 50px;
  background: #000;
}

JavaScript

setTimeout(function(){
  elem = document.createElement('p');
  document.body.appendChild(elem);
  console.log('count <p>: ', document.querySelectorAll('p').length);
  setTimeout(function(){console.log(34235);}, 3000);
  alert('alert');
},500);