It's well documented how global.asax error handling doesn't capture web services but can be worked around by implementing a custom soap extension. This provides a form of exception injection.
Other than wrapping methods in your asp.net ajax web services (scriptservice with pre 3.5 json serializer) in try...catch... or having to rewrite objects used by service to encapsulate this so that you can log errors, wonder if anyone out there has come up with elegant global implementations of this? From msdn, it looks like there is no equivalent of a ProcessMessage method (analogous to soap extension strategy but for json).
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