562.js

gistfile1.js

var Gadget = (function() {
	var counter = 0,
			NewGadget;
			
	NewGadget = function () {
		counter += 1;
	};
	
	NewGadget.prototype.getLastId = function () {
		return counter; 
	};
	
	return NewGadget;
}());

var iphone = new Gadget();
iphone.getLastId();
var ipod = new Gadget();
ipod.getLastId();
var ipad = new Gadget();
ipad.getLastId();