There's actually some really good stuff for this now.  I have experimented a bit with haste.  Cabal install it, then use the haste-inst to install haskell libraries as javascript, then compile your program with it and then load it into your browser.  The only downside is that some lower level functions don't work, so  like I couldn't use the vector library in an application I had already written.  But if you keep that in mind while you are developing it works pretty well.  You should be able to do a text adventure no problem.

There is also GHCJS which is set to release on the next ghc release (it only works with new versions of ghc) which promises to go even further to get those last few bits of code working.  But of course it isn't out just yet.