[jimmaswell]

Why would you choose to develop for a game in JavaScript anyway? The language devs use for Unity tends to be C#. The design of the language fits the framework much more. I've been using C# with Unity and using JavaScript on webpages for years and JavaScript has always been much more cumbersome and error-prone to write nontrivial logic in. So many errors all the time that would've been found at compile-time in C#. Maybe Unity's JS is different; I haven't used it.

[JabavuAdams]

Unity's JS is different. It's all Mono under the hood. It's not at all like working with browser Javascript.

[Cacti]

It's not JavaScript, it's UnityScript. Basically since everything that's not compiled to native code is run through Mono.

By default Unity provides support for UnityScript, C#, and Boo. However, since it's just IL all the way down, you can easily use IronPython, IronScheme, ClojureCLR, F#, etc., etc. just as easily.