listeners : {
         'beforeshow' : function() {
                         var b=[];
             Ext.Ajax.request({
                         url : 'XXX.jsp',
                         params : {
                             type : 'load'
                         },
                         success : function(response, options) {
                             // alert(response.responseText);
                             for (var _i = 0; _i < 5; _i++) {
                                 var _data={};
                                 b.push(Ext.apply(_data, {
                                 id : _i
                             }))
                             }
                         }
                         alert(b.length);
                     });
                     alert(b.length);
         }
     }
显示在Ext.ajax.request外的的b.length为0,
要怎么取到经过Ext.ajax.request回调赋值后的b呢？

var b=[];写在外边。。