Scrolling Content Area

I need some help from anyone!! I can’t seem to figure out a solution. I am making images of up and down arrows for a user to scroll through some text content. But I cannot make the up and down arrows work in javascript for mozilla. First, I tried using .doScroll function but that wouldn’t work in Mozilla but would in I.E. I found a site that had a example of something close of what I want to do but I am completely confused by their code so I don’t know how to manipulate it to do what I want it to do. Here is the site:
http://www.dynamicdrive.com/dynamicindex11/scrollc2.htm# – this is what I am talking about - the two arrows moving the content but I want users to be able to press the arrows so it can move the content a little at a time instead of scrolling all content once you put the mouse over the arrow. Is there maybe another alternate way to write this code or somehow fix the one I am using?

KSP