Yes you're right, we can have the same effect using asmx webservice and let ScriptService serialize the message as JSON. I found Dave Ward's blog to be usefull about this topic.

In my case, I want to route all AJAX request through request queue, so I can fire several AJAX request all at once. The queue will process those request one at a time, ensuring there is only one connection open. Web browser have a limit on number of simultaneous connection. I want all request to be served deterministically in correct order, no matter how wild user clicking all widgets on page.

I implement the queue as a reusable Javascript class, and set the Jayrock proxy to use my class as rpc channel. This way, I can still invoke server side through Jayrock proxy member function. Contrast this with Dave Ward approach using low level jQuery.ajax().

I haven't explore asmx proxy class deeply, maybe there's also similar mechanism inside it.

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Jimmy Merari