求教ExtJS中XML的读取

参照extJS实用开发指南上的代码写的，但是读不出XML文件里的内容
html文件<html><head>
</head>
<link rel = "stylesheet" type="text/css" media="all" href="ext-3.2.0/resources/css/ext-all.css"/>
<script type="text/javascript" src="ext-3.2.0/adapter/ext/ext-base.js"></script>
<script type="text/javascript" src="ext-3.2.0/ext-all.js"></script>
<script type="text/javascript" src="ext-3.2.0/ext-lang-zh_CN.js"></script>
<script type="text/javascript" language="javascript">

function showUrl(value){
return "<a href='http://"+value+"'>"+value+"</a>";
} Ext.onReady(function(){
var store=new Ext.data.Store({
url:'hello.xml',
reader:new Ext.data.XmlReader({
record:"row"},
["id","name","organization","homepage"])
});
var coIM = new Ext.grid.ColumnModel([{header:"项目名称",dataIndex:"name",sortable:true},
{header:"开发团队",dataIndex:"organization",sortable:true},
{header:"网址",dataIndex:"homepage",renderer:showUrl}]);
var grid = new Ext.grid.GridPanel({
renderTo:'hello',
title:'java develop',
height:200,
width:600,
cm:coIM,
store:store,
autoExpandColumn:2
});
store.load();
});

</script>
<body>
<div id="hello"/>
</body></html>
xml文件的内容<?xml version="1.0" encoding='UTF-8'?>
<dateset>
<row>
<id>1</id>
<name>EasyJWeb</name>
<organization>EasyJF</organization>
<homepage>www.easyjf.com</homepage>
</row>
<row>
<id>2</id>
<name>jfox</name>
<organization>huihoo</organization>
<homepage>www.huihoo.org</homepage>
</row>
<row>
<id>3</id>
<name>jdon</name>
<organization>jdon</organization>
<homepage>www.jdon.com</homepage>
</row>
<row>
<id>4</id>
<name>springside</name>
<organization>springside</organization>
<homepage>www.springside.org.cn</homepage>
</row>
</dataset>
xml和html放在同一个文件夹下