unction (member_id, role_id) {
                    var $this = this;
                    $.ajax({
                       url : "{{urlfor "BookMemberController.ChangeRole"}}",
                        data : { "identify" : $this.book.identify,"member_id" : member_id,"role_id" : role_id },
                        type :"post",
                        dataType : "json",
                        success : function (res) {
                            console.log(res);
                            if (res.errcode ==