store.proxy = new Ext.data.HttpProxy({url:path});

示例：

var ad_store = new Ext.data.JsonStore({            fields: ["id", "title1", "title2", "content", "pid", "position", "publish_time", "end_time", "pic_url", "link_url","ad_tag", "total_read_num"],            url: 'php/action/ad_oper.php?op=query_all&start=0&limit=15&type=' + type,            totalProperty: 'total',            root: 'data'        });

修改url：

tbar: [{                text: '增加',                handler: addAd            }, {                text: '筛选游戏:',                border: false            }, {                id: 'select_game',                xtype: "combo",                hideLabel: true,                mode: "local", //由于数据已定义所以必须写成local                triggerAction: 'all', //想要加载所有项就要这么写，网上这么说的，我没试过不写                editable: true,                emptyText: "请选择",                store: game_info_store,                valueField: 'gid',                displayField: 'nameCN', //不写这项的话，你会发现下拉项是空的没内容哦                listeners: {                    'select': function(src, val) {                        gid = val.data.gid;                        url = 'php/action/ad_oper.php?op=query_all&start=0&limit=15&gid='+gid+'&type=' + type;                        ad_store.proxy = new Ext.data.HttpProxy({url:url});                        ad_store.reload();                    }                }            }],