λ> main
Null

import Test.WebDriver
import Test.WebDriver.JSON (ignoreReturn)
import Test.WebDriver.Session
import Control.Monad.IO.Class
import Data.Aeson.Types

chromecfg :: WDConfig
chromecfg = useBrowser chrome defaultConfig
            { wdHost           = "localhost"
            , wdPort           = 4444
            , wdHTTPRetryCount = 50
            , wdCapabilities   = caps
            }
  where
    caps :: Capabilities
    caps = defaultCaps { javascriptEnabled = Just True }

main :: IO WDSession
main = do
  s <- runSession chromecfg getSession
  runWD s $ do
    let js = "Object.defineProperty(navigator, 'languages', {get: function() {return ['foo', 'bar'];}, });"
    ignoreReturn $ executeJS [] js
    liftIO . print =<< (executeJS [] "navigator.languages" :: WD Value)
  return s