ext解析XML

Ext.onReady(function(){
                //alert();
                var store = new Ext.data.Store({
                    url: 'hello.xml',
                    reader: new Ext.data.XmlReader({
                        record: 'country'
                    }, [{
                        name: 'country',
                        mapping: 'cid'
                    }])
                });
                store.load()
                alert(store.getCount());
            });

xml 文件 

<?xml version="1.0" encoding="utf-8"?> 
<conf> 
    <country name="China"> 
        <cid>China</cid> 
            <province name="ShanXi"> 
                <pid>ShanXi</pid> 
                <city>TaiYuan</city> 
                <city>DaTong</city> 
                <city>YunCheng</city> 
            </province> 
    </country> 
    <country name="America"> 
        <cid>America</cid> 
            <province name="Florida"> 
                <pid>aaa</pid> 
                <city>bbb</city> 
                <city>ccc</city> 
                <city>ddd</city> 
            </province> 
    </country> 
</conf>