demo.js

/* global global: true */
function Constructor () {
  this.instanceMethod();
  Constructor.staticMethod();

  function privateFunction () {
    global.console.log('Hello, I am an internal function! XD');
  }
}

Constructor.prototype.instanceMethod = function () {
  global.console.log('Hello, I am an instance method! :3');

  this._privateMethod();
};

Constructor.prototype._privateMethod = function () {
  global.console.log('Hello, I am a "private" function! ಠ_ಠ');
};

Constructor.staticMethod = function () {
  global.console.log('Hello, I am a static function! :D');
};

var constructor = new Constructor();