asmx web service returning xml instead of json in .net 4.0

Question

i have just upgraded a test copy of my site to asp.net 4.0 and have noticed a strange issue that only arises when i upload the site to my server.

the site has an asm

Answer 1

Are you sure .NET 4 is installed on your server?

The ScriptHandlerFactory's "type" string in .NET 4 is:

System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"

ASP.NET 4 now includes that in its default web.config at the machine level. So, you shouldn't need any mapping to the ScriptHandlerFactory in your project's web.config, 3.5 or 4.