JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://code.jquery.com/jquery-3.5.0.min.js"></script>
<pre id="mypre" style="background-color:grey"></pre>

JavaScript

var val = `"<!DOCTYPE html>\n
<html>
  \n
  <body>
    \n
    <h1>My First Heading</h1>
    \n
    <p>My first paragraph.</p>
    \n\n
  </body>
  \n
</html>
"`;


$(document).ready(function(){
  val = val.replace(/^"(.*)"$/, '$1');
  val = val.replace(/(?:\r\n|\r|\n)/g, '');
  $("#mypre").text(val);
});