ext js library

Firfox error message: ext is not defined

<link type="text/css" rel="stylesheet" href="/js/ext-2.2/resources/css/ext-all.css"/>
<script type="text/javascript" src="/js/ext-2.2/adapter/ext/ext-base.js"></script>
<script type="text/javascript" src="/js/ext-2.2/ext-all.js"></script>