JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://code.jquery.com/jquery.js"></script>
<a href="http://www.zoomtek.dk">ZoomTek Kurser</a><br />
<div id="redbox">Postkasse</div>

CSS

div#redbox{
	position:absolute;
	left:100px;
	top:100px;
	width:100px;
	height:100px;
	background-color:red;
}
body#top div.redboxon{
	color:white;
	left:500px;
	display:block;
}

JavaScript

var demo =
{
	ready:function()
	{
		$("a").toggle
		(
			function($e)
			{
				
				$e.preventDefault();
				$('div#redbox').addClass('redboxon');
			},
			function($e)
			{
				$e.preventDefault();
				$('div#redbox').removeClass('redboxon');
			}
		);
	}
};
$(document).ready(demo.ready);