How can i send a JSON object to a webmethod using jQuery?
Please refer to this article by Dave Ward. It is a complete tutorial on doing this stuff. Also you will find there other great jquery/ASP.net stuff.
EDIT:- Dave is calling method without any arguments, you can replace empty data property with actual data you want to send:
$.ajax({
type: "POST",
url: "Default.aspx/GetDate",
data: "{'name':'tiger1','hobbies':['reading','music']}",//PUT DATA HERE
contentType: "application/json; charset=utf-8",
dataType: "json",