JSFiddle - React, Tailwind, and code Playground

HTML

<link id="Link1" rel="stylesheet" type="text/css"
      href="http://cdn.sstatic.net/stackoverflow/all.css" 
      onload="handle404Error(this)"
      onerror="handle404Error(this, true)"
/>

<div id="output"></div>

JavaScript

var output= document.getElementById('output');

function handle404Error(el, failed) {
  if(failed || (el.sheet.cssRules && !el.sheet.cssRules.length)) {
    output.innerHTML= output.innerHTML + el.id+ ': '+ el.href+' failed to load!<br>';
  }
  else {
    output.innerHTML= output.innerHTML + el.id+ ': '+ el.href+' loaded successfully!<br>';
  }
}