[hluska]

I have never tried this service, so please don't take this as an endorsement, but someone in another thread mentioned he/she is selling javascript on a service called CodeCanyon.

(citation - http://news.ycombinator.com/item?id=2795952)

[eswat]

CodeCanyon is also a sister site of ThemeForest, so if the OP is looking for something similar this would probably have the best fit.

[mmccomb]

That's exactly the sort of service I was looking for - I can't believe I haven't come across it before! Thanks.