You thought Coffeescript was haml? Um...no...

CoffeeScript does look a bit like HAML. But actually, to write CoffeeScript, you write CoffeeScript, not HAML, and then you can either compile it with the coffee command (which does output JS) and run the JS on the server OR on the client (see http://jashkenas.github.com/coffee-script/#scripts). Actually more often its on the server because people don't like running it in the browser (I don't see a good reason to avoid CoffeeScript in the browser really, but he says its "not recommended" on his site so.. people don't feel its recommended.)

The reason to avoid running the CoffeeScript compiler in the browser is that it takes time to compile a script, time which can be easily saved for the user by sending them a pre-compiled version. Of course running the CS compiler in the browser is great for development, but in a production environment every millisecond counts.

That's not what I'm talking about. People were saying to avoid CS in the browser altogether.