Without any isolation

by NesterOne

HTML

<link rel="stylesheet" href="https://dl.dropboxusercontent.com/u/595391/base.css">
<script src="http://localhost:8080/jasperserver-pro/scripts/jasper.js"></script>
<div id='sidebar'>
    <div>
         <h2>Third-Party Header</h2>

        <textarea>Third Party Text</textarea>
    </div>
    <div id='report'>
        <div>
             <h2 class="jrs">Report Header</h2>

            <textarea class="jrs">Third Party Text</textarea>
        </div>
    </div>
</div>

CSS

/* the selector user specified to style his own reports */

/* The selector we added for visualize's reports */
 #sidebar textarea {
    background-color: yellow;
}

JavaScript

$(document.body).addClass('jrs');