而且打开页面时不会报错，一会儿错误就弹出了
IE版本 ：IE 8
Extjs版本：4.0.2a
代码如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<link type="text/css" rel="Stylesheet" href="../ext-4.0.2a/resources/css/ext-all.css" />
<script type="text/javascript" src="../ext-4.0.2a/builds/ext-core-debug.js"></script>
<script type="text/javascript" src="../ext-4.0.2a/ext-all-debug.js"></script>
<title>Framework Demo</title>
<script type="text/javascript">
Ext.onReady(function () {
Ext.create('Ext.container.Viewport', {
layout: 'border',
items: [{
xtype: 'container',
region: 'north',
height: 50,
padding: '5 10 5 10',
html: 'this is the head content'
}, {
title: 'Options',
region: 'west',
autoScroll: true,
padding: '0 0 5 5',
collapsible: true,
width: 200,
split: true
}, {
id: 'tabmain',
xtype: 'tabpanel',
region: 'center',
padding: '0 5 5 0'
}],
renderTo: Ext.getBody()
})
});
</script>
</head>
<body>
</body>
</html>
那位高手帮我看看错在哪里，不胜感激呀！
