引入ExtJS4必要的js和css文件，在js部分調用ExtJS入口文件，彈出Hello World!
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title></title>
<link rel="stylesheet" type="text/css" href="resources/css/ext-all.css" />
<script type="text/javascript" src="ext-all-debug.js"></script>
<script type="text/javascript" src="ext-all.js"></script>
<script type="text/javascript" src="bootstrap.js"></script>
</head>
<body>
<script type="text/javascript">
Ext.onReady(function () {
Ext.MessageBox.alert('標題','hello world!');
});
</script>
</body>
</html>
