//track document and outbound link clicks
//courtesy of google analytics-help-tracking group
function initClickTracking() {
    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
            var path = hrefs[l].pathname + hrefs[l].search;
            var isDoc = path.match(/(?:doc|exe|pdf|ppt|xls|zip)($|\&)/);
            if (isDoc) startListening(hrefs[l],"mousedown",trackExternalLinks);
        }
    }
}

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

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 (typeof(pageTracker) == "object") pageTracker._trackPageview(lnk);
}