JSFiddle - React, Tailwind, and code Playground

HTML

<iframe sandbox="allow-scripts" srcdoc='
  <script>
    var blob = new Blob(["abc"]);
    var fr = new FileReader();
    fr.readAsText(blob);
    fr.onerror = () => document.body.innerText = "fail"
    fr.onload = () => document.body.innerText = fr.result
  </script>
'></iframe>