Cross Domain Restrictions

Cross Domain javascript requests aren't allowed. Because of hackers, I cannot make an ajax call from www.mystore.com to api.ultracart.com and use the result to modify my web page in any way. Yes, there are hacks and creative solutions to work around this, but they are numerous limitations to them and we highly doubt you wish to build your ecommerce solution on such unreliable means of remote communication.

The solution is to place a script on your site that talks server-to-server to the ultracart server. By doing this, and directing all remote calls to your relay script, there are no security restrictions. This solution works very well.