Track outgoing links with google analytics

gat.js

(function(){
	function addEventListener(element, event, listener) {
		if (typeof listener != 'function')
			return;

		if (event == 'ready' && element == document){
			if (/(loaded|complete)/.test(document.readyState)) {
				listener();
				return;
			}

			if (element.addEventListener) {
				window.addEventListener(event, listener, false);
				document.addEventListener('DOMContentLoaded', listener, false);
			}
			if (element.attachEvent) {
				document.attachEvent("onreadystatechange", listener);
				window.attachEvent( "onload", listener );
			}
		} else {
			if (element.addEventListener)
				element.addEventListener(event, listener, false);
			if (element.attachEvent)
				element.attachEvent('on'+event, listener);
		}
	}

	// track external links
	(function(){
		if (typeof _gaq != 'object') return;

		var rules = [];
		var dwnFileExts = [];
		var useTrackPageview = false;
		var useTrackEvent = true;

		for (var i=0; i<_gaq.length; i++)
		{
			switch (_gaq[i][0]) {
				case '_setExtLinksRules':
					rules = _gaq[i].slice(1);
					delete _gaq[i];
					break;
				case '_setExtLinksDownloadableFileExtensions':
					dwnFileExts = _gaq[i].slice(1);
					delete _gaq[i];
					break;
				case '_setExtLinksUseTrackPageview':
					useTrackPageview = _gaq[i].slice(1);
					if (typeof useTrackPageview == 'object' && useTrackPageview.length>0)
						useTrackPageview = useTrackPageview[0];
					delete _gaq[i];
					break;
				case '_setExtLinksUseTrackEvent':
					useTrackEvent = _gaq[i].slice(1);
					if (typeof useTrackEvent == 'object' && useTrackEvent.length>0)
						useTrackEvent = useTrackEvent[0];
					delete _gaq[i];
					break;
			}
		}

		var aTags = document.getElementsByTagName('A');
		if (!aTags.length) return;

		var a, ahost, chost = typeof _gbh != 'string' ? ((document.location.hostname || document.location.host).replace(/:[0-9]+$/,'')+'.').split('.').slice(-3,-1).join('.') : _gbh;

		chost = new RegExp('(^|\\.)'+chost+'$', 'i');

		for (var i=0; i<aTags.length; i++) {
			a = aTags[i];
			ahost = (a.hostname || a.host).replace(/:[0-9]+$/,'');
			if (a.href=="" || !/^https?:$/.test(a.protocol) || a.elEventExists || chost.test(ahost)) continue;

			a.gaLink = String(ahost + '/' + a.pathname.replace(/^\//,'') + a.search + a.hash).replace(/^www\./,'').replace(/\/+$/,'');

			addEventListener(a, 'click', function(event) {
				var a = (event.currentTarget || event.target || event.srcElement);
				if (a.tagName.toLowerCase() != 'a' || !a.gaLink) return true;

				var evtCat, evtAct, evtVal;

				for (var i=0; i<rules.length; i++)
					if ( RegExp(rules[i][0], 'i').test(a.gaLink) ) {
						evtCat = rules[i][1];
						evtAct = rules[i][2];
						evtVal = a.gaLink;

						window._gatPushFunc = function(useTrackPageview, useTrackEvent, evtCat, evtAct, evtVal) {
							if (useTrackPageview)
								_gaq.push(["_trackPageview", "/" + evtCat + "/" + evtVal]);
							if (useTrackEvent)
								_gaq.push(["_trackEvent", evtCat, evtAct, evtVal]);
							if ($.browser == 'msie')
								window['_gatPushFunc'] = null;
							else
								delete window['_gatPushFunc'];
						}

						 // hack for download links
						if (RegExp('\\.('+dwnFileExts.join('|')+')$', 'i').test(a.gaLink))
							window.setTimeout('window._gatPushFunc(' + useTrackPageview.toString() + ', ' + useTrackEvent.toString() + ', "' + evtCat + '", "' + evtAct + '", "' + evtVal + '");', 10);
						else
							window._gatPushFunc(useTrackPageview, useTrackEvent, evtCat, evtAct, evtVal);
					}

				return true;
			});

			a.elEventExists = true;
		}
	})();

	// track ajax-requests by GA
	addEventListener(document, 'ready', function() {
		if (typeof jQuery != 'undefined')
			jQuery(document).ajaxSend(function(e, x, s) {
				if (typeof _gaq == 'object')
					_gaq.push(['_trackPageview', s.url]);
			});
	});

})();

(function() {
	var ga = document.createElement('script'); ga.type = 'text/javascript';	ga.async = true;
	ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
	var s = document.getElementsByTagName('script')[0];	s.parentNode.insertBefore(ga, s);
})();

include this into html

<script type="text/javascript">
  var _gaq = _gaq || [];
  _gaq.push(["_setAccount","UA-0000000-00"]);
  _gaq.push(["_setExtLinksRules",[".*","external-link","click"]]);
  _gaq.push(["_setExtLinksDownloadableFileExtensions","rar","zip","exe","torrent"]);
  _gaq.push(["_setExtLinksUseTrackPageview",true]);
  _gaq.push(["_trackPageview"]);

  (function() {
    var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
	ga.src = 'path/to/gat.js';
    var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
  })();
</script>