var oPrev;
var oNext;
var oTarget;
var oImgName;
var oImgDesc;
var gActImg = 0;

function ci(aId){
	gActImg = aId;
	oTarget.src = gImgArr[aId];
	if(aId == (vImgCnt -1)){
		//Last 
		oPrev.src = "/img/back.gif";
		oNext.src = "/img/forwardgrey.gif";
		
	}else{
		if(aId == 0) {
			//First
			oPrev.src = "/img/backgrey.gif";
			oNext.src = "/img/forward.gif";
		}else{
			//All in the middle
			oPrev.src = "/img/back.gif";
			oNext.src = "/img/forward.gif";
		}
	}
	oImgName.firstChild.nodeValue =gImgLblArr[gActImg];
	oImgDesc.firstChild.nodeValue =gImgDescArr[gActImg];
}

function initPage(){
	oTarget = document.getElementById( "big_img");
	oPrev = document.getElementById( "prev");
	oNext = document.getElementById( "next");
	oImgName = document.getElementById( "img_name");
	oImgDesc = document.getElementById( "img_desc");
	oPrev.src = "/img/backgrey.gif";
	ci(0);
}
function fPrev(){
	if(gActImg != 0){
		gActImg--;
		ci(gActImg);
	}
}
function fNext(){
	if(gActImg != (vImgCnt -1)){
		gActImg++;
		ci(gActImg);
	}
}
initPage();