在用ExtJS 动态加载树时的问题，
下载了ExtJS2.0.2版本的包，照着例子做的，自己做了三个文件：tree.js,tree.html,tree.txt
当运行时，只能看到树的根节点，而tree.txt中的文件都没加载进去，tree.txt的内容是安json来写的。
请高手们帮帮忙，我的问题在什么地方
===============================
tree.js
===============================
/*
* Ext JS Library 2.0.2
* Copyright(c) 2006-2008, Ext JS, LLC.
* licensing@extjs.com
*
* http://extjs.com/license
*/
Ext.onReady(function(){
var Tree = Ext.tree;
var tree = new Tree.TreePanel({
el:'tree',
loader: new Tree.TreeLoader({
dataUrl:'tree.txt'
})
});
var root = new Ext.tree.AsyncTreeNode({id:"1",text:"根节点"});
//debugger;
tree.setRootNode(root);
// render the tree
tree.render();
root.expand();
});
-==============================================
tree.html
===============================================
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gbk">
<title>test tree111</title>
<link rel="stylesheet" type="text/css" href="../../resources/css/ext-all.css" />
<!-- GC -->
<!-- LIBS -->
<script type="text/javascript" src="../../adapter/ext/ext-base.js"></script>
<!-- ENDLIBS -->
<script type="text/javascript" src="../../ext-all.js"></script>
<script type="text/javascript" src="testTreejs1.js"></script>
<!-- Common Styles for the examples -->
<link rel="stylesheet" type="text/css" href="../examples.css" />
</head>
<body>
<script type="text/javascript" src="../examples.js"></script><!-- EXAMPLES -->
树
<div id="tree" style="overflow:auto; height:300px;width:250px;border:1px solid #c3daf9;"></div>
</body>
</html>
============================================
tree.txt
============================================
[
{id:"10",text:'01',children:[
{id:"101",text:'01-01',leaf:true},
{id:"102",text:'01-02',children:[
{id:"1011",text:'01-02-01',leaf:true},
{id:"1012",text:'01-02-02',leaf:true}
]},
{id:"102",text:'01-03',leaf:true}
]},
{id:"20",text:'02',leaf:true}
]
------解决方案--------------------
<script type="text/javascript" src="tree.js"></script>
js引用不对！