Firstly, we need to understand that even with the hype of Web 2 it just an upgrade of Web 1. Therefore, why do we need to dismissed that we have in Web 1 when an upgrade version comprise of Web 1 inclusive of the upgrade in Web 2. For instance, regardless how fancy you were able to develop but when the viewer (your website visitor) can't optimized it then it was a real waste of time you spent.

Personally I don't think I see much problem creating a compatible javascript framework if it's correctly done, well I do ignore the fancy effect of DHTML maybe because I prefer the system to work properly compare to the effect.

http://www.thinkvitamin.com/features/ajax/...onous-scripting