I have been meaning to have this bookmarked and I am sure I did it but somehow keep missing it whenever I needed it to refer to people. One of the sweet lady at Macromedia Adobe, Jen Dehaan have blogged about it long back. We have it hosted as html reference for our team in our internal server, I have been longing to have it on my own site for the archives and personal reference too.
Download the Standalone HTML ActionScript 2.0 Language Reference from the Flash Docs Page.
Download the zipped equivalent PDF version or visit the online LiveDocs.
