I am trying to develop a vertical scroller - it is a UL with a fixed height to only show a few list items, then with up and down controls, the user can scroll through.
There is 3 bottons on top and 3 on bottom, to move up and down one item, then to jump 3 items and finally to move to the top or bottom.
I have created this all and it is kind of working, it moves up and down one and jumps up and down 3, but the problem comes if I move down and then half way through use a different method, ie start scrolling one place, but then jump down.
For usability, I have set the buttons to disappear when the user is at the top or bottom. This works if you use the same method, once or 3 times scroll. If you mix it up, it breaks and the buttons won't hide.