User Availability using jquery and json not working on server in asp.net

I have a textbox on blur function.I'm calling a Jquery function which work call a webmethod on the cs file returning true and false.I am using JSON.This whole functionality is working on local and when i give a alert(resu开发者_StackOverflow社区lt.d).It gives proper result when working on the server i.e 0 or 1.But when i do that on server,it returns undefined.I have used json.

Based on the information provided in the question I can suggest to please run your page in firefox and look in the console tab in firebug, you can have better idea from there and can judge from there what is the issue. Also please set in you web config so that the console can show you the full error if there is any.