Do Javascript programmers program in terms of function applications, or do they program in terms of sequences of state-changing operations?
If they do the first, then Javascript is a functional language. But without even a function composition or application operator (or function), it's obvious tht Javascript is not intended to be functional. It's an imperative/OO language with lambdas, like Common Lisp.
There is no canonical definition of "functional language", so I guess it depends on your definition. JavaScript is an OO-language, but it is possible to program in a functional style, just as with many other OO languages.
But typical JavaScript development will not teach you the functional programming paradigm, if that is what you ask.
If you really want to learn functional programming, you are better off trying something that at least makes you go out of your way to code in a non-functional style. Anywhere from all the way off the deep end with Haskell to Clojure and F# being good choices from personal experience.
