JSFiddle - React, Tailwind, and code Playground

HTML

<a href="#" id="loadLink">About</a> 

  <iframe id="content" name="content" align="top" src="index.html" 
      frameborder="0" width="100%" height="1200px" scrolling="no">
  </iframe>

JavaScript

$("#content").hide();

$("#loadLink").click(function() {
    $("#content").hide();
    $("#content").attr('src', 'http://mysite.com/newpage.html');
});

$("#content").load(function() {
    $(this).slideDown();
});