JSFiddle - React, Tailwind, and code Playground

HTML

<html><head><script type="text/javascript" src="chrome-extension://aggiiclaiamajehmlfpkjmlbadmkledi/lib/popup.js" async=""></script><script type="text/javascript" src="chrome-extension://aggiiclaiamajehmlfpkjmlbadmkledi/lib/tat_popup.js" async=""></script></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">&lt;html&gt;
&lt;head&gt;
&lt;/head&gt;
&lt;body&gt;
&lt;/body&gt;
hello world
&lt;/html&gt;
</pre></body></html>

JavaScript

var marks = document.getElementsByTagName("body");
    for(var i = 0, l = marks.length; i < l; i++)
    {
        var mark = marks[i];
        mark.innerHTML = mark.innerHTML.replace('&lt;', '<');
        mark.innerHTML = mark.innerHTML.replace('&gt;', '>');
        mark.innerHTML = mark.innerHTML.replace('&amp;', '&');
    }