Okay, I see where you're coming from now.  My concern with Crockford's example is that memory is allocated for each private function whenever the constructor is called.  While this is useful in some cases, I feel that it's a bit of an edge case and that it is typically more pragmatic to be memory-conscious and stick with methods that are private by convention (the convention being a leading underscore).  It's a style I picked up from popular JavaScript libraries and frameworks like [Backbone](https://github.com/jashkenas/backbone/blob/master/backbone.js#L332).

Thanks for making the change.  I'm open to having an example of a Crockford-style private method defined in the constructor, but it this point that may be better suited for a followup Pull Request.