Private Members in Javascript

private.js

function Test() {
  var _secret = "12345"; 

  // private method
  function __private() {
    return _secret;
  }

  // publicly accessible method and can access private vars & methods
  this.priviledged = function() {
    return __private();
  }
}

Test.prototype.niceTry = function() {
    return this.hasOwnProperty("__private") ? this.__private : "nice try!";
}

var test = new Test();

console.log(test.priviledged());
console.log(test.niceTry());