Prototype JavaScript library documentation
Sergio Pereira has written up some very nice unofficial documentation for Prototype, the leading javascript library for Ajax applications. Its also the library underneath Rails’ ajax support. Sergio has even done some API style docs for the major objects. Definitely worth a print out.
Aside: what is up with the script.aculo.us server? Every other time I try to check out the demos or wiki there, its not responding. Do they just need to upgrade the server?