json - ASP.NET WebService test form -

is possible configure default asp.net webservice test form support json? mean test form built in in .net framework...

currently have webservice decorated [scriptservice], when testing using built in test form page, returns xml...i assume, happens because test page sends content-type xml default.

thanks

edit (example):
have class:

public class person {   public string firstname { get; set; }   public string lastname { get; set; } } 

now have asp.net webservice:

[scriptservice] public class personservice : webservice {   [webmethod]   public person getdave()   {     person dave = new person();      dave.firstname = "dave";     dave.lastname = "test";      return dave;   } } 

when call webservice web page using jquery ajax, receive json person object {"firstname":"dave","lastname":"test"} (not string) in javascript, when invoking webservice asp.net webservice test form (when right click on asmx file , use "preview in browser"),

it returns:

<?xml version="1.0" encoding="utf-8" ?>  <person xmlns:xsi="http://www.w3.org/2001/xmlschema-instance" xmlns:xsd="http://www.w3.org/2001/xmlschema" xmlns="http://tempuri.org/">   <firstname>dave</firstname>    <lastname>test</lastname>  </person> 

what want, when invoke service test page, see same output:

{"firstname":"dave","lastname":"test"} 

you can use code below

[webmethod(description = "some description")] [scriptmethod(responseformat = responseformat.json)] public string functionname() {                // return json data     javascriptserializer js = new javascriptserializer();     string retjson = js.serialize(object);     return retjson; } 

and need add reference.

update

here link explain extending existing asp.net web service support json

hope helps