debug javascript sliding on MAC & iOS Safari ONLY

I am working on custom coded wordpress site for a client. Home page has ad banner images sliding down the screen as the user scrolls, and then stopping before the next element. It works fine in ALL browsers EXCEPT Safari on Mac and iPad. Need someone who is able to troubleshoot it. See the page here [login to view URL] and scroll down the page to see vertical ad banners (Calvin Klein Jeans slide down and stop before the next horizontal banner. Does NOT work in Safari on Mac (works in Safari on PC and all other browsers!)