// Initialize Banner Services
var BannerIndex = -1;

function InitializeBanners(index) {
   BannerIndex = index;
   ValidateBannerButtons ();
   DisplayBanner ();
}

function DisplayBanner () {
   var bTable = null;
   if ((banners!=null) && (BannerIndex>=0) && (BannerIndex<banners.length)) {
       bTable = GetDocumentElement ("bannerContainer");	
       if (bTable!=null) {
           bTable.style.backgroundImage = "url(" + banners[BannerIndex]+")";
       }
   }
}

function MovePrevBanner () {
   if (BannerIndex>0) {
       BannerIndex = BannerIndex-1;
   }
   else {
       BannerIndex = banners.length-1;
   }
   DisplayBanner ();
}

function MoveNextBanner() {
   if (BannerIndex==banners.length-1) {
       BannerIndex = 0;
   }
   else {
       BannerIndex = BannerIndex+1;
   }
   DisplayBanner ();
}

function ValidateBannerButtons () {
   var bNextButton = null;
   var bPrevButton = null;
   var bNext = true;
   var bPrev = true;
   
   if (BannerIndex!=-1) {	
	   bPrevButton = GetDocumentElement ("bannerPrevButton");	
	   bNextButton = GetDocumentElement ("bannerNextButton");
	   if ((bPrevButton!=null) && (bNextButton!=null)) {
		   if (banners.length==1) {
				bNext = false;
				bPrev = false;						   
		   };
	   };
	   bNextButton.style.display = ((bNext==true)? "block" : "none");
	   bPrevButton.style.display = ((bPrev==true)? "block" : "none");
   };
}