Experimenting with javascript closures: inheritance

closure_inheritance.js

mynamespace = window.mynamespace || {};

mynamespace.Parent = function (param) {

  var _privateProperty = param;

  return {
    getTwice : function () {
        return _privateProperty * 2;
    }
  };
};


mynamespace.Child = function (param) {
  var _that = mynamespace.Parent.apply(this, arguments);

  _that.getHalf = function () {
    return _that.getTwice() / 4;
  }

  return _that;
}; 

(function () {
  var myParent  = new mynamespace.Parent(6);
  var myChild   = new mynamespace.Child(8);

  console.log(myParent.getTwice());
  console.log(myChild.getTwice());
  console.log(myChild.getHalf());

}());