ExtJs.ajax.request的异步请求

Ext.Ajax.request({    url:'./ck_xxcx?city_id='+id+'',//params:{city_id:'id'},method:'get',scope:this,timeout:10000,success: function (response, options) { //获取结果将相关信息绘制在地图(封装服务端传送的数据                    Ext.MessageBox.alert('成功', '从服务端获取结果: ' + response.responseText);              },             failure: function (response, options) {                     Ext.MessageBox.alert('失败', '请求超时或网络故障,错误编号：' + response.status);               } });