title: Google Analytics eCommerce data with payment gateway callback
body: <p>We use WorldPay as our payment gateway and we've specified the callback URL to be myurl.com/payment.php, however worldpay doesn't actually redirect to this URL, it passes some parameters to it, ie, whether the payment was successful, how much for, etc and then displays the result through a worldpay server.</p>
  
  <p>What I want to do is implement Google Analytics eCommerce tracking (instructions found here: <a href="http://code.google.com/apis/analytics/docs/tracking/gaTrackingEcommerce.html" rel="nofollow">http://code.google.com/apis/analytics/docs/tracking/gaTrackingEcommerce.html</a> ). But this requires javascript which isn't enabled on the worldpay server.</p>
  
  <p>I could do an immediate meta refresh to myurl.com/analytics.php which displays, aesthetically the same screen, but is actually on our server, so the JS will work.</p>
  
  <p>The question is, how do I pass the cartID, if i'm using a meta refresh?</p>