Turns out the BBCode story for server-side Javascript is kinda pitiful.

- I evaluated Redactor (<http://imperavi.com/redactor/>), but it's just not going to work since people want more than just formatted text. I can't easily extend raw HTML with things like hider tags without forcing the user to ultimately be able to edit HTML. 

        <div class="hider" name="My Hider">My Secrets</div>

    Can't quite get behind that. I burned an entire day trying to make it work, but it's just not pretty for the end user.
- I tried SCEditor (<http://www.sceditor.com/>) which I really liked. Easy for me to extend. I even extended it with some cool BBCode components to see how easy it was:

        [hider=My Hider]My Secrets[/hider]

        [tabs]
          [tab=Intro]
            This is the intro
          [/tab]
          [tab=Conclusion]
            This is how it all ends
          [/tab]
        [/tabs]

    ...But there is no straightforward way to use its parser to also do the BBCode->HTML render on the server.

So far I'm experimenting with extending an open-source javascript BBCode library. It hasn't been maintained in a long time, but I'm having decent progress with it. I may be able to use SCEditor and then keep SCEditor's BBCode parser in sync with my server-side BBCode parser.

I'm sure doing a lot of spelunking down rabbit holes. :)