more class emulation in js

Animal

		<script type="text/javascript">

			var Animal = function(){};

			Animal.prototype.breath = function(){
				console.log('inhale');
			};
			Animal.prototype.heart = function(){
				console.log('beating heart');
			};
			var Dog = function(){};
			// Dog inherits from Animal
			Dog.prototype = new Animal;

			Dog.prototype.wag = function(){
				console.log('wag tail');
			};

			var Cat = function(){};
			//Cat inherits from Animal
			Cat.prototype = new Animal;

			Cat.prototype.meow = function() {
				console.log('meow i\'m a cat');
			}


			var dog = new Dog;
			dog.wag();
			dog.breath();

			var cat = new Cat;
			cat.heart();
			dog.breath();
			cat.meow();

		</scrip