How to call a web service from ajax in asp.net

public static CBTDLCFDBEntities context = new CBTDLCFDBEntities();
        [WebMethod]
        public static void SaveQuestionSetting(Subject subject)
        {
try
            {
                context.Subjects.Add(subject);
                context.SaveChanges();
            }
            catch (Exception ec)
            {
                //
            }

$(document).ready(function () {
            var messageLabel = $('#lblResult');
            // messageLabel.hide();
            $('#btnSaveQuestionNoSetting').click(function () {
                //var tlength = $("input:text").length;
                var subjIds = new Array();
                var qNums = new Array();
                var i = 0;
                $(".inline :input").each(function () {
                    var count = $(this).attr('name');
                    subjIds[i] = count;
                    qNums[i] = $(this).val();
                    i++;
                });
$.ajax({
                    url: "../SettingService.asmx/SaveQuestionSetting",
                    method: 'POST',
                    data: { subjectIds: JSON.stringify(subjIds), qCount: JSON.stringify(qNums) },
                    //async: true,
                    contentType:"application/x-www-form-urlencoded;charset=UTF-8",
                    success: function (response) {
                        console.log(response.d);
                        messageLabel.text("Saved successfully");
                        var btn = $('#btnSaveQuestionNoSetting');
                        btn.removeClass("btn-blue");
                        btn.addClass("btn-success");
                        btn.val("Saved");
                        messageLabel.fadeOut(5000);
                        btn.removeClass("btn-success");
                        btn.addClass("btn-blue");
                    },
                    error: function (errMsg) {
                        console.log("An error has occured");
                        console.log(errMsg);
                    }
                });

            });
        });