Handling post requests from widgets - redirecting to landing page

I wondered how do you folks handle post requests and particularly ajax requests from widgets. E.g. I have a widget returning data from web service. This works fine whilst running from visual studio but once I run it on server, the url changes and deafaults to /landingpage/ controller rather then the /widget/ controller and that breaks the ajax. What is the best way forward? What is the official way to handle post requests in widgets?

Thanks,

L.