Sinatra Ruby Model-View-Controller framework against XMLHTTPRequest

Hi, I don´t understand which is the advantage of using Sinatra in my aplications against XMLHttpRequest in Javascript. I´m using Nokia Places via XMLHTTPRequest with get method in JavaScript and parsing directly the JSON response because I can't implement successfully the request with Sinatra framework.
Could somebody tell me the advantages of Nokia Places with Sinatra framework, and the advantages of Nokia Places with XMLHTTPRequest in Javascript?

Thanks.

Hi

there is nothing wrong with using the Places API directly from within a browser. We just decided to build our demo application as a server side application, as this allowed us to make "clean usage" of all Places API features, without mixing in concepts/solutions specific the browser platform (Same-Origin-Policy, CORS, JSONP, how to modify headers).

Andreas

Thank you Andreas.