Пример:
Определение объекта window.
"HTML"
Is 'window' a window? <b></b>
"Живой пример jQuery"
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<link href="http://slyweb.ru/css/jqueryiframe.css"
rel="stylesheet" type="text/css"/>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.5.0/jquery.min.js"></script>
<script>
$(document).ready(function(){
$("b").append( "" + $.isWindow(window) );
});
</script>
</head>
<body class="iframe">
Is 'window' a window? <b></b>
</body>
</html>