JavaScript inheritance (borrowing and setting prototype)

inheritance.js

(function() {

    Parent.prototype.say = say;
    Child.prototype = new Parent();

    function Parent (name) {
        this.name = name || 'Paul';
    }

    function say () {
        console.log(this.name);
    }

    function Child (name) {
        Parent.apply(this, arguments);
    }

    var parent = new Parent('John');
    parent.say();

    var kid = new Child('Alan');
    kid.say();
})();