Javascript Not Parsing Nested Bbcode

I have coded a Javascript bbcode similar to the one I'm using to write this message. It also incorporates a live preview box like the one I see below. The only problem I'm facing a

Solution 1:

Three solutions:

1. Write a parser. This will produce the best solution but takes a non-trivial amount of effort.

2. Find a BBCode parsing library. Probably as good as #1 in quality and substantially easier.

3. Add a negative lookahead to the inside of each tag regex and continuously apply until no match. E.g.:

   \[quote\]((?:[^](?!\[quote\]))*?)\[\/quote\]
   

   This will capture the inner quote, then once its replaced, the outer one. Not nearly as clean as the other two but probably the quickest fix.