JSFiddle - React, Tailwind, and code Playground

HTML

<html>
<head>
  <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/crypto-js/3.1.9-1/crypto-js.min.js"></script>
  <script>
  function loadResource(path) {
    var xhttp = new XMLHttpRequest();
    xhttp.onreadystatechange = function() {
      if (this.readyState == 4 && this.status == 200) {
        var cs = CryptoJS.SHA256(this.responseText);
        if (btoa(cs) == 'NjBiMTllNWRhNmE5MjM0ZmY5MjIwNjY4YTVlYzExMjVjMTU3YTI2ODUxMzI1NjE4OGVlODBmMmQyYzhkOGQzNg==' ||
            confirm('Bootstrap is NOT the latest version 4.3.1, load anyway ?')
           ) {
          var link = document.createElement('link');
          link.rel = "stylesheet";
          link.href = path;
          document.head.appendChild(link);
        }
        else {
           var err = document.getElementById('error');
           err.title = "Component version error !";
           err.innerHTML = '&nbsp;⚠️';
        }
      }
    };
    xhttp.open("GET", path, true);
    xhttp.send();
  }

  loadResource(
              //'https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css' // newest boostrap
              'https://stackpath.bootstrapcdn.com/twitter-bootstrap/2.0.4/css/bootstrap-combined.min.css' // old legacy
              );
  </script>
</head>

<body>
<div style="position: absolute; top: 20px; left: 20px;">
    <button class="btn btn-success">My cool button</button><span id='error'></span>
</div>
</body>
</html>