urchin = new urchin();
urchin.trackDownload = "mp3|ppt|doc|pdf|ram|rm";
urchin.trackLinks();

function urchin(){
	this.trackDownload = '';
	this.trackLinks = function(){
		var a = document.getElementsByTagName('a');
		var internalLink = new RegExp("^(http|https):\/\/"+location.host, "i");
		var isDownload = new RegExp("("+this.trackDownload+")$", "i");
		for(var i = 0; i < a.length; i++){
			if(internalLink.test(a[i].href)){
				if(this.trackDownload && isDownload.test(a[i].href)){
					a[i].onclick = function(){
						urchinTracker(this.href);
					};
				};
			};
		};
	};
};