Ask HN: "best" UI JavaScript library/framework?
I have an idea for another application and want to do it "right" this time just to learn new stuff. This will be desktop-like web application. Right now I am trying to decide which library/framework to learn and use for browser part. I really like Cappuccino look'n'feel, but their Objective J look weird to me. Is there is something like Cappuccino with plain JavaScript or it's better to invest some time into learning this Objective J thing? Any thoughts are really appreciated!
Update: I am looking for open source libraries/frameworks =)