Redirection in an epub

I realize each epub reader interprets code individually, so one answer to one may not work to another.
But, I realize, if epub is html, i should be able to make it where readers can be guided where to go.
I know the javascript techniques using location or window open but before I try it later any suggestions on how to do it from some whom have already is welcome. An epub is technically supposed to be in its own environment. I know that javascript by default allows a breakage to that environment and thus why many ereaders dont allow for this or the other. But, I don't see why doing an internal action should be rejected.
I will try later to get a page in my test epub to read what page I came from and accept me or take me to another page based on the reading. thanks again