// Get the __utmz cookie value. This is the cookies that
// stores all campaign information.
// utmcsr = campaign source
// utmcmd = campaign medium
// utmctr = campaign term (keyword)
// utmcct = campaign content (used for A/B testing)
// utmccn = campaign name
// utmgclid = unique identifier used when AdWords auto tagging is enabled
// custom segmentation is stored in __utmv cookie value