gistfile1.js

(function(message){ 
  alert(message);
})('hello!');

// -------------------------

var Test = function() {
  var message = 'hello';
  return {
    say: function() {
      alert(message);
    }
  }
};

t = new Test();
t.say();

// -------------------------

var Test = function() {
  this.message = 'hello';
};

Test.prototype.say = function() {
  alert(this.message);
};

t = new Test();
t.say();