var Banners = Array('images/Tickets1.png', 'images/Tickets2.png', 'images/Tickets3.png');
var CurrentBanner = 0;//make variable for index 0 of below array.
function DisplayBanners() {
   if (document.images) {
      document.RotateBanner.src = Banners[CurrentBanner];//RotateBanner is name of image object whose source is Tickets1.png. 
      CurrentBanner++;
      if (CurrentBanner == Banners.length) {
         CurrentBanner = 0;
      } 
      setTimeout("DisplayBanners()", 2000);
   }
}