classic_inheritance.js

function Rectangle(w,h) {
    this.width = w;
    this.height = h;
}
Rectangle.prototype.area = function() { 
    return this.width * this.height;
};

function PositionedRectangle(w,h,x,y) {
    Rectangle.call(this, w, h);
    this.x = x;
    this.y = y;
}

PositionedRectangle.prototype = heir(Rectangle.prototype);
PositionedRectangle.prototype.constructor = Rectangle;