page1.html

<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>Simple Ext JS 4 Page</title>
    <link rel="stylesheet" type="text/css" href="http://extjs.cachefly.net/ext-4.0.2/resources/css/ext-all.css" />
    <script type="text/javascript" src="http://extjs.cachefly.net/ext-4.0.2/ext-all-debug.js"></script>
    <script>
      //TODO: move that to a separate file
      Ext.onReady(function(){
        Ext.MessageBox.alert('test','Test Message is here');
        new Ext.Panel({
          width: 200,
          height: 200,
          renderTo: 'place-for-panel',
          title: 'A panel'
        });
      });
    </script>
  </head>
  <body>
    <p>This is a simple page where an ExtJS 4 panel will be rendered</p>
    <!-- here is a placeholder for a panel-->
    <div id="place-for-panel"></div>
  </body>
</html>