Best content type to serve JSONP?

Question

I have a webservice that when called without specifying a callback will return a JSON string using application/json as the content type.

When a callback

Answer 1

Use application/javascript. In that way, clients can rely on the content-type without having to manually check whether a response has padding or not.

Answer 2

Use application/json as per rfc4627.txt if what you return is plain JSON.

If you return JavaScript (which is really what JSONP is), then use application/javascript as per rfc4329.txt