How do you use CoffeeScript? It need to be compiled, so - you write code in CoffeScript, compile it, and insert real JavaScript on your site?
Doesn\'t it take a lot
When you are first learning coffeescript, you will almost certainly want to do your compilation manually during development, because you will probably find, as most of us do, that you need to be able to look at the javascript code in order to debug and find out what's going on. The more fluent and comfortable you become with coffescript, the less often you will need to refer to the javascript code.
I think this will probably be true no matter what your level of expertise in javascript. If you are a javascript pro, you will be dependent on looking at stuff you are familiar with, until you start to figure out how coffeescript works. On the other hand, if you are completely or partially unfamiliar with all the quirks and subtleties of javascript, such as prototypes, the javascript approach to scope and globals, and all the rest, you'll find yourself digging into javascript references, and cross-referencing the javascript code with your coffescript code, until you get familiar with it.