Topic: Press key with top button

I have a problem that I believe is simple but I don't quite know where to start.  I am running my infocast in "browser" mode using the guide in the infocast forum.  Does anyone know if there is a way to make something happen when I press the top button?  All I really want is for it to pass a keyboard character when touched.  I saw a post somewhere that said the button shows up as a keyboard, but I don't really know where to go from there.  Could someone give me some advice?  Basically, I want the button to pass a scancode that I can detect with javascript.  Seems doable.  Thanks!

-=Izrun