SpiderMonkey is what happens to be built into a web browser; it’s used by Mozilla browsers. :P
What you meant, I think, is having the code simply be run in people’s browsers. The thing is, nomics are inherently multiplayer, so if the code ran in the people’s browsers, each person’s instance would have to connect to the other instances and… eh, it’s just a lot easier and simpler to run it on the server side.
SpiderMonkey is what happens to be built into a web browser; it’s used by Mozilla browsers. :P
What you meant, I think, is having the code simply be run in people’s browsers. The thing is, nomics are inherently multiplayer, so if the code ran in the people’s browsers, each person’s instance would have to connect to the other instances and… eh, it’s just a lot easier and simpler to run it on the server side.
I might put it on GitHub at some point.