The really cool thing about this is that you can also use alternative languages which compile to Javascript. I develop Cursive, an IDE for Clojure and Clojuresc

The really cool thing about this is that you can also use alternative languages which compile to Javascript. I develop Cursive, an IDE for Clojure and Clojurescript, and one of my users has a native app written in Clojurescript published on the App Store. He had to jump through a few hoops to get the REPL working but once he got it going he could edit code on his device live. It's really cool to see. I'm hoping to add debugging support using the Webkit Remote Debugging Protocol, which will make it even nicer.