JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.23/jquery-ui.min.js"></script>
<div id="foo"></div>

CSS

#foo {
 background-color: #000000;
 color: #FFFFFF;
 width: 400px;
 height: 400px;  
 padding: 20px;    
}

JavaScript

var 
 $foo = $('#foo')
;

$foo
 .text( $foo.outerWidth() )
;