Combination of Functional/Prototypal Inheritance

prototypical-functional-inheritance.js

var Animal = function () {

    var helloCount = 0;
    var self = this;
    //priviledge methods
    this.AnimalHello = function() {
        helloCount++;
        console.log(self.Name + ' says hello (animalHello)');
    };

    this.GetHelloCount = function (callback) {
        callback.call(null, helloCount);
    }

};

Animal.prototype = {
    Name: 'Generic',
    IsAnimal: true
};

var Sheep = function (name) {

    var sheep = new Animal();
    //use parasitic inheritance to extend sheep
    //http://www.crockford.com/javascript/inheritance.html
    sheep.Name = name || 'Woolie'
    sheep.SheepHello = function() {
        this.AnimalHello();
        var self = this;
        this.GetHelloCount(function(count) {
            console.log('i (' + self.Name + ') have said hello ' + count + ' times (sheepHello anon callback)');
        });
    }

    return sheep;

};

Sheep.prototype = new Animal();
Sheep.prototype.isSheep = true;

var sheepie = new Sheep('Sheepie');
var lambie = new Sheep('Lambie');

sheepie.AnimalHello();
sheepie.SheepHello();
lambie.SheepHello();

From http://stackoverflow.com/questions/16659326/simple-javascript-inheritance-using-extend-and-module-pattern

Refer http://webreflection.blogspot.com.es/2010/02/javascript-override-patterns.html for a class provider with prototypical inheritance