Has anyone thought about Io in the browser

Just asking because I come from a javascript background. Reading and trying out Io just makes me question why no one's tried to replace javascript with it. Just seems to me Io would make a better javascript than javascript. It's prototype based, functional, and object-oriented. Has anyone considered making browser plugins or talking about it to say mozilla? 
I've tried google's new dart and it's just more of the same really, if I could use Io in the browser that would be neat. I've gone through the wikibook and already wrote a few programs so I'm not confused or anything. I know they're different lol, still I'd be much happier using Io everyday than javascript or dart. haha