JSFiddle - React, Tailwind, and code Playground

HTML

<!doctype html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>Embedded Web Worker Test</title>
<script type="text/javascript">
  function log_worker_msg(worker_msg) {
    var frag = document.createDocumentFragment();
    frag.appendChild(document.createTextNode(worker_msg));
    document.querySelector("#worker_log").appendChild(frag);
  }
</script>
<script type="text/javascript">
var aFileParts = ["var xmlhttp = \'XMLHttpRequest: \' + ( ( \'function\' === typeof XMLHttpRequest ) ? \' YES\' : \' NO\' );var file_reader = 'FileReader: ' + ( ( \'function\' === typeof FileReader ) ? \' YES\' : \' NO\' );var websockets = \'Websockets: \' + ( ( \'function\' === typeof WebSocket ) ? \' YES\' : \' NO\' );var myVar = \"Test results: \" + xmlhttp + \", \" + file_reader + \", \" + websockets;self.onmessage=function(oEvent){self.postMessage(myVar)};"];
var oBuilder = new Blob(aFileParts, { "type" : "text\/javascript" });
var obj_url = window.webkitURL.createObjectURL(oBuilder) || window.URL.createObjectURL(oBuilder);
  document.worker = new Worker(obj_url);
  document.worker.onmessage = function (oEvent) {
    log_worker_msg( oEvent.data);
  };
  window.onload = function() { document.worker.postMessage(""); };
</script>
</head>
<body><div id="worker_log"></div></body>
</html>