/*
********************************************************************************
Filename    : gatag.js

Author      : goodwebpractices.com

Created     : 2008-03-04

Description : Adds a click event to anchor (<a>) tags linking to specified file 
              types so that Google Analytics can track the file.

-------------------------------------------------------------------------------
Modification History / Change Record
-------------------------------------------------------------------------------

Date        Programmer       Description of Changes
----------  ---------------  -------------------------------------------------
2008-03-04  M.Masterson      Copied script from net. Cleaned-up format and 
                             added documentation block.

2008-03-14  M.Masterson      Added Office 2007, CAD and Project File Types to RE
-------------------------------------------------------------------------------
General Notes
-------------------------------------------------------------------------------
1.) Place this file on all pages immediately before the Google Analytics 
    tracking code. 

2.) Source:
    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 == location.host) {
         var path = hrefs[l].pathname + hrefs[l].search;
         var isDoc = path.match(/(?:accdb|accde|accdr|accdt|avi|cad|css|doc|docm|docx|dotm|dotx|eps|exe|jpg|js|mov|mp3|mpp|pdf|png|potm|potx|ppam|ppsm|ppsx|ppt|pptm|pptx|rar|svg|txt|vsd|vxd|wma|wmv|xlam|xls|xls|xlsb|xlsm|xlsx|xltm|xltx|zip)($|\&)/);
         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(pageTracker) == "object") 
   	pageTracker._trackPageview(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); 

}