[Haskell-beginners] Non ghc specific FRP (using uhc js backend)

Hi, I am currently informing myself about FRP. Looking at the Elerea paper (http://sgate.emt.bme.hu/documents/patai/publications/PataiWFLP2010.pdf) I read that it is ghc specific because of mutable references. I am trying to use the js backend of uhc and that does not support this. I have tried to use other FRP libraries with uhc (by compiling a file which does nothing but import the library) and all failed because of something missing in Control.Concurrent. So I am wondering: Is it a property FRP that it needs something like mutable references for an efficient implementation. Is there a FRP library that can be used (or can be changed so that it can be used) with uhc and its js backend? Thanks! Nathan