Hm...If you could do that for every letter key, set the "go back" link to the back space key and the "continue" link to the enter key, place the usual on-page variable junk at the end of the text, and find a small "blinking cursor" gif to go at the end of the page (i.e. after all the crap the player types), you could probably get somewhere, right?
I mean, I imagine there would be some ugly side-effects, though.