Cross-site requests: the "callback" parameter
As the JSON-RPC 1.1 draft spec standardizes making requests via HTTP GET, I propose that an additional HTTP GET parameter be standardized such as "JSON-response-callback". This parameter would not be passed to the method invoked by the request. The data passed into the callback function would be the JSON-RPC procedure return object.
For example, if I invoked a method via the following URL: http://services.com/math/add?JSON-response-callback=displaySum&num1=1&num2=1