OOP

    function Animal(voice){
        this.voice = voice || 'grunt';
    }
    Animal.prototype.speak = function(){
        console.log(this.voice);
    }

    function Cat(name, color){
        Animal.call(this, 'Meow');
        this.name = name;
        this.color = color;
    }

    Cat.prototype = Object.create(Animal.prototype);
    var fluffy = new Cat('Fluffy','black');
    console.log(fluffy);