// http://groups.google.com/group/analytics-help-basics/browse_thread/thread/847b2d73e0b53302
// http://www.goodwebpractices.com/roi/track-downloads-in-google-analytics-automatically.html

if (document.getElementsByTagName) {
        // Initialize external link handlers
        var hrefs = document.getElementsByTagName("a");
        for (var l = 0; l < hrefs.length; l++) {
                //protocol, host, hostname, port, pathname, search, hash
                if (hrefs[l].protocol == "mailto:") {
                        startListening(hrefs[l],"click",trackMailto);
                } else if (hrefs[l].hostname.substring(0,4) == location.host.substring(0,4)) {
                        var path = hrefs[l].pathname + hrefs[l].search;
                        var isDoc = path.match(/(?:doc|eps|exe|jpg|pdf|png|ppt|svg|vsd|xls|zip|tar|gz|patch)($|\&)/);
                        if (isDoc) {
                                startListening(hrefs[l],"click",trackExternalLinks);
                        }
                } else {
                        startListening(hrefs[l],"click",trackExternalLinks);
                }
        }
}

function startListening (obj,evnt,func) {
        if (obj.addEventListener) {
                obj.addEventListener(evnt,func,false);
        } else if (obj.attachEvent) {
                obj.attachEvent("on" + evnt,func);
        }

}

function trackMailto (evnt) {
        var href = (evnt.srcElement) ? evnt.srcElement.href : this.href;
        var mailto = "/mailto/" + href.substring(7);
        if (typeof(urchinTracker) == "function") urchinTracker(mailto);

}

function trackExternalLinks (evnt) {
        var e = (evnt.srcElement) ? evnt.srcElement : this;
        while (e.tagName != "A") {
                e = e.parentNode;
        }
        var lnk = (e.pathname.charAt(0) == "/") ? e.pathname : "/" + e.pathname;
        if (e.search && e.pathname.indexOf(e.search) == -1) lnk += e.search;
        if (e.hostname != location.host) lnk = "/external/" + e.hostname + lnk;
        if (typeof(pageTracker) == "object") pageTracker._trackPageview(lnk); 
}