This makes me wonder what the point of writing 'var' is if it doesn't tell you the type of the variable.
Note: This is just my thinking, I don't know if it's the actual reason
Javascript and Coffeescript try to solve this in different ways, most people think that JavaScript's method sucks, and many are not fond of CoffeeScript's non-locality. Personally, I think that demanding variable declaration is still the best option (possibly except for interactive sessions).