My JavaScript Module Pattern

app.js

;(function (w, d, undefined) {
  
  'use strict';
  
  var app = (function () {
    
    var exports = {};
    
    var _privateMethod = function () {
      return 'private method';
    };
    
    exports.publicMethod = function () {
      return 'public method';
    };
    
    return exports;
    
  })();
  
  w.app = app;
  
/*
  this is possible:
  app.publicMethod();
  
  this is not possible:
  app._privateMethod();
  app.privateMethod();
*/
  
})(window, document);