求帮忙看看NET配合AJAX有关问题

$(document).ready(function(){    $("#UserLogin").click(function(){        var logintype=$("#LoginType").val();        var username=$("#UserName").val();        var userpwd=$("#UserPwd").val();        if(username=='')        {            alert('请输入用户名！');            return false;        }        if(userpwd=='')        {            alert('请输入密码！');            return false;        }        $.ajax({            type:"POST",            contentType: "application/json",            url:"/user/login.ashx",            data:"{LoginType:"+logintype+",UserName:"+username+",UserPwd:"+userpwd+"}",            dataType: 'json',            success: function(result) {     //回调函数，result，返回值                $("#Login")(result);            },            error:function(){                alert('错误');            }        });    });});

IUserLogin userlogin = new IUserLogin();        public void ProcessRequest(HttpContext context)        {            string LoginType = Convert.ToString(context.Request.QueryString["LoginType"]);            string UserName = Convert.ToString(context.Request.QueryString["UserName"]);            string UserPwd = Convert.ToString(context.Request.QueryString["UserPwd"]);            UserInfo info = new UserInfo();            if (LoginType == string.Empty || LoginType == null || LoginType == "")                context.Response.Write("参数错误！");            if (LoginType == "id")                info.Userid = Convert.ToInt32(UserName);            if (LoginType == "user")                info.UserName = UserName;            if (LoginType == "email")                info.Email = UserName;            info.UserPwd = UserPwd;            context.Response.Write(userlogin.UserLogin(LoginType, info));        }