在线运行代码 - 菜鸟教程

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>菜鸟教程(cainiaoplay.com)</title>
<script src="https://cdn.staticfile.org/jquery/1.6.2/jquery.min.js"></script>
</head>
<body>
	
<script>
(function(){
	var sub = jQuery.sub();

	sub.fn.myCustomMethod = function(){
        return 'just for me';
	};

	sub(document).ready(function() {
		alert(sub('body').myCustomMethod());
	});
	
	alert(typeof jQuery('body').myCustomMethod); //underfine
})();
</script>
 
</body>
</html>

源代码

动行结果