      beforeSend: function () {
                        // 禁用按钮防止重复提交
                        $("#btn_up").attr({disabled: "disabled"});
                    },
                    //成功返回
                    success: function (data) {
                        $("#btn_up").removeAttr('disabled');
                        if(data.code == "200"){
                            layer.msg('更新成功', {
                                time: 2000, //2s后自动关闭
                     