import GHCJS.DOM.Document (getBody)
import GHCJS.DOM.EventM (on, preventDefault)
import GHCJS.DOM.GlobalEventHandlers (keyDown)
import Reflex.Dom hiding (preventDefault)
import Web.KeyCode

main :: IO ()
main = mainWidget $ do
  doc <- askDocument
  Just body <- getBody doc
  kp <- wrapDomEvent body (`on` keyDown) $ do
    preventDefault -- This 'preventDefault' is here to prevent
                   -- the browser's default behavior when keys
                   -- like <F1> or the arrow keys are pressed.
                   -- If you want to preserve default behavior
                   -- this can be removed, or you can apply it
                   -- selectively, only to certain keypresses.
    i <- getKeyEvent
    return i
  lastKeyPressed <- holdDyn Nothing $
    Just . keyCodeLookup . fromEnum <$> kp
  display lastKeyPressed