$.ajax({

            type: "POST",

            url: ".aspx/getSubjectDirection",

            data: JSON.stringify({ "data":data }),

            dataType: "json",

            contentType: "application/json;charset=utf-8",

            success: function (data) {

            },

            error: function (data) {

                alert(“”);

            }

        });

        [WebMethod]

        public static string getSubjectDirection(string data)

        {

            return null;

        }