OOP javascript object inheritance constructor prototype

oop.js

/**
 *  Animal constructor
 **/
var Animal = function(name) {
    this.name = name;
};

Animal.prototype.speak = function() {
    console.log('my name is ' + this.name);
};

/**
 *  Dog constructor
 **/
var Dog = function(name) {
    Animal.call(this, name); // super
};

// inherite from Animal constructor
Dog.prototype = new Animal();

Dog.prototype.bark = function() {
    console.log('wouf wouf');
};


var puppy = new Dog('alpine');

puppy.speak();
puppy.bark();