JavaScript prototype inheritance quiz

prototype-quiz.js

(function () {
    'use strict';
    
    var foo, bar1, bar2;
    
    function Foo () {
        this.counter = { i : 0};
        this.counter2 = 0;
    }

    function Bar() {    
    }

    foo = new Foo();
    Bar.prototype = foo;

    Bar.prototype.sayHello = function () {  
        console.log('sayHello(): counter1 =',
                    this.counter.i,
                    ', counter2 =',
                    this.counter2,
                    '\n');
        this.counter.i += 1;
        this.counter2 += 1;
    };

    bar1 = new Bar();
    bar2 = new Bar();

    foo.sayHello();
    bar1.sayHello(); 
    bar2.sayHello();
    foo.sayHello();
}());