[aneel13]

Thanks for the response. Still its not clear how to go about. Let me give details on the problem again.

1) If I change country on checkout page, then an ajax call happens which first runs the service/API and gets the response and after the service response the fields needs to be changed on the frontend (e.g. for US no postal field, for UK no city field etc.). Meaning should I change the HTML at frontend accordingly as soon as I get the service response? But then the problem is the backend validation rules will apply differently, I need to change them aswell when place order is clicked. So what to call after my service response? Should I call some xcart function to update the fields which will automatically update the frontend html and backend validation rules?

2) I will make a separate ticket on the second issue. Because first one is dependent on it.