http://jsfiddle.net/j127/UTxqF/2/

Subclassing in JavaScript with parent's arguments

function Vehicle(manufacturer) {
    this.manufacturer = manufacturer;
}

Vehicle.prototype.sayHello = function () {
    alert('Hi there');
};

function Unicycle(manufacturer, spokes) {
    Vehicle.call(this, manufacturer);
    this.spokes = spokes;
}

Unicycle.prototype = Object.create(Vehicle.prototype);
Unicycle.prototype.constructor = Unicycle;

Unicycle.prototype.sayWater = function () {
    alert('water');
};

var vehicle, unicycle;
v = new Vehicle('Tesla');
u = new Unicycle('Bob', 30);

v.sayHello();
u.sayHello();

console.dir(v);
console.dir(u);