index.html

<!DOCTYPE html>
<html>
<head>
	<title>extnd demo</title>
	<script src="extnd.js"></script>
</head>
<body>

	<script>
	var Animal = Class.extnd({
		init: function(name) {
			this.name = name;
		},

		getAge: function() {
			return '9 million years old';	
		}
	});

	var Bird = Animal.extnd({
		wings: 'wings',

		init: function(name) {
			this._super.apply(this, arguments);
			console.log('I am a bird, animal tells me my name is', this.name);
		}
	});

	var HummingBird = Animal.extnd(Bird).extnd({
		init: function(name) {
			this._super.apply(this, arguments);
			console.log('Hummingbirds have', this.wings);
			console.log('Hummingbirds are', this.getAge());
		}
	});

	var hummingBird = new HummingBird('FlappyPappy');
	</script>

</body>
</html>