ขอตัวอย่างการใช้ Ajax ใน ASP.NET หน่อยค่ะ จะเอามาดัดแปลงใช้ในหน้า Login ค่ะ

function Authentication() {
            ShowSuccessed();
            username = $('#username')[0].value;
            password = $('#password')[0].value;
            $("#user-input").hide();


            $.ajax({
                type: "POST",
                dataType: "json",
                url: "IPadQuestionnaireService.asmx/Authentication",
                data: '{"username": "' + username + '", "password":"' + password + '"}',
                contentType: "application/json; charset=utf-8",
                success: function (message) {
                    if (message == 'NOT-FOUND') {
                        ShowFailed();
                    }
                    else {
                        $(this).delay(30000);
                        var item = message.split('|')
                        $.cookie("fullname", item[0]);
                        $.cookie("sale-id", item[3]);
                        $.cookie("sale-code", username);
                        $.cookie("p-code", $('#password')[0].value);

                        if ($("#lang1")[0].checked)
                            $.cookie("default-language", $("#lang1")[0].value);
                        else
                            $.cookie("default-language", $("#lang2")[0].value);



                        $.cookie("accessibleProjcet", message.split('|')[2]); // item 0 is fullname, item 1 is user code    
                        window.location = "select-project.html";
                    }
                },
                error: function (xhr, msg) {
                    $("#au-success").hide();
                    ShowFailed();

                }
            });

        }