On the one hand, adding to standard browser engines support for multiple scripting languages, instead of just Javascript, is a cool idea, and something that probably should have happened a long time ago.

On the other hand, the fact that this currently requires the user to install it first, seems to make it less portable than a compile-to-JS solution like Opal (http://opalrb.org/). At least until standard support for multiple scripting languages actually does get introduced to browser engines.

Cool project, regardless!