Overriding the Bad way

gistfile1.js

function Animal(){}
 
Animal.prototype = {
  name: 'animal',
  sayHello: function sayHello(){
    return 'Hi, my name is ' + this.name  + '!';
  }
};
 
function Dog(){}
 
Dog.prototype = new Animal();
Dog.prototype.sayHello = function sayHello(){
  return 'Hello, my name is ' + this.name + '!';
};
 
var dog = new Dog();
dog instanceof Animal; //True
dog.sayHello(); //Hello, my name is animal!