Crockford.inheritance.js

var oldObj = {
  first: function() {},
  second: function() {}
};

var newObj = Object.create(oldObj);

newObj.third = function() {};

var myDoppelganger = Object.create(newObj);

myDoppelganger.first();


//For IE < 9
if (typeof Object.create != 'function') {
  Object.create = (function() {
    var Temp = function() {};
    return function (prototype) {
      if (arguments.length > 1) {
        throw Error('Second argument not supported');
      }
      if (typeof prototype != 'object') {
        throw TypeError('Argument must be an object');
      }
      Temp.prototype = prototype;
      var result = new Temp();
      Temp.prototype = null;
      return result;
    };
  })();
}