Is it possible to post data to JsonP? Or does all data have to be passed in the querystring as a GET request?
I have alot of data that I need to send to the service,
You could use a CORS Proxy using this project. It would direct all traffic to an endpoint on your domain and relay that information to an external domain. Since the browser is registering all requests to be on the same domain we are able to post JSON. NOTE: This also works with SSL certificates held on the server.