"If you look at the history of JavaScript it was originally designed to do things like have a push button, but it moved beyond that to become what nobody expected; namely a programming language for web applications.
I believe that with the current race to improve javascript performance, JS stands a good chance of being the language to use both on the server and the client in the near future. It is interesting to read about Google's motivations, since they are somewhat on both sides of the table on this issue. It's just as important to them that other browsers improve their JS runtime as that Chrome does it, in order to support their JS heavy applications like GMail and Google Reader.