Wrapping a javascript "class"?
You could wrap your whole file in a namespace, as described here.

Of all the possibilities, this is the one I like the most:

var YourNamespace = (function () {
   var Message = function (div) {
      ...
   }
   var aPrivateFunction = function () { ... }
   ...
   return {
      'Message': Message
   };
})();


This lets you define private functions, like aPrivateFunction, not visible outside YourNamespace. You can access Message as YourNamespace.Message.