ext大虾请帮帮忙

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%
String path = request.getContextPath();
String basePath = request.getScheme() + "://"
+ request.getServerName() + ":" + request.getServerPort()
+ path + "/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<link rel="stylesheet" type="text/css" href="<%=basePath%>css/ext-all.css" />
<script type="text/javascript" src="<%=basePath%>js/ext-base.js"></script>
<script type="text/javascript"
src="<%=basePath%>js/ext-all.js"></script>
<script>
Ext.onReady(function(){
    var panel = new Ext.Panel({
     renderTo:'pad',
        title:'hello'
       width:300,
       height:200,
        html:'<h1>nishidahuaidan</h1>'
    });});
</script>
<title>testEXT</title>
</head>
<body><div id="pad"></div></body>
</html>报错了 我刚接触EXT 不太熟悉