Comment by seliopou

There is also a compiler for OCaml bytecode to JavaScript, called js_of_ocaml[0]. It's been around for a while, but I've only recently started using it. It's got a pretty good FFI, and makes futures-based programming via lwt[1] very convenient.

[0]: http://ocsigen.org/js_of_ocaml/

[1]: http://ocsigen.org/lwt/