EXT同步问题、mask方法、combobox的load完毕的判断

 this.btnOk = new Ext.Button({ 
             text        : '确定', 
             disabled    : true, 
             scope       : this, 
             handler     : function(){ 
                Ext.Msg.show({ 
                    title:'更新', 
                    msg: '操作更新，请确认 ！', 
                     buttons: Ext.Msg.OKCANCEL, 
                     fn: function(_btn, _text){ 
                         if(_btn == 'ok') { 
                 try { 
                    if(!isUndefined(this.getEl())){ 
                         this.getEl().mask('模型上传中，请稍后...','x-mask-loading'); 
                     }
                    



                    后台同步操作数据库（Action）



                 } finally { 
                    if(!isUndefined(this.getEl())){ 
                         this.getEl().unmask(); 
                     }
                 } 
                 Ext.Msg.alert('同步',  '操作成功'); 
                        } 
                     }, 
                     animEl: 'elId', 
                     icon: Ext.MessageBox.WARNING, 
                     scope   : this 
                }); 
             } 
        });

 comboCity.on({
             'select':function(combo,record,index){
                          comboQb.clearValue();
                          comboZc.clearValue();
                          comboTown.reset();
                          comboDisplaylevel.clearValue();
                          newOrgManageFormWin.getEl().mask('正在获取分支机构的信息，请稍后...','x-mask-loading'); 
                          storeTown.reload({
                                params:{branchno:comboCity.getValue(),_node:_node},
                                callback : function(r, options, success) { 
                                                 newOrgManageFormWin.getEl().unmask(); 
                                             } 
                                 });
                          storeDisplayLevel.reload( {params : { type:'1'}});
                        }
            });