JSOn y JSONP: When ajax calls are in a different domain from the server.

JSON versus JSONP Tutorial y https://github.com/craic/json_jsonp_tutorial

[~/sinatra/sinatra-json_jsonp(master)]$ pwd -P
/Users/casiano/local/src/ruby/sinatra/sinatra-json_jsonp
[~/sinatra/sinatra-json_jsonp(master)]$ git remote -v
origin  git@github.com:craic/json_jsonp_tutorial.git (fetch)
origin  git@github.com:craic/json_jsonp_tutorial.git (push)