Change HTML page to make auto-scrolling smoother (JavaScript / jQuery)

I have an existing simple portfolio webpage for photos at [login to view URL] The page scrolls automatically depending on mouse position. The task is: make this scrolling smooth. It's one single HTML file (look at source in browser) and uses jQuery for the scrolling. Everything works fine, but in some browsers the scrolling is not smooth. I think this might be due to the content being in a scrollable DIV. I'm not sure to solve it, but maybe it would be smoother if the top part would be an iFrame and the rest a normal scrollable page, or if it was not a scrollable DIV but simply a DIV in a DIV with overflow: none. Anyways, I want the page to look and behave exactly like it already does, but with smooth scrolling. It must work in all major browsers. You can simply save the page source in the browser, work on that and send it back, so there is no need for FTP. There's one AJAX call in it, but it always returns the same data, so you can just save it as a static file as well, for your testing. In your bid, please include - price - short description of how you would do it (1 sentence) - optional: link to a HTML/JS page you built in the past