var nowNum = 0;
function galleryNext(allCnt){
	var nextNum = nowNum+1;
	var cnt = allCnt-3;

	if(nextNum>cnt){
		nextNum = cnt;
	}

	if(nextNum==cnt){
		document.getElementById("gallerynext").style.display = "none";
	}else{
		document.getElementById("galleryprev").style.display = "block";
		document.getElementById("gallerynext").style.display = "block";
	}

	for(i=0;i<allCnt;i++){
		if(i==nextNum){
			document.getElementById("gallery"+i).style.display = "inline";
			i++;
			document.getElementById("gallery"+i).style.display = "inline";
			i++;
			document.getElementById("gallery"+i).style.display = "inline";
		}else{
			document.getElementById("gallery"+i).style.display = "none";
		}
	}

	nowNum = nextNum;
}
function galleryPrev(allCnt){
	var prevNum = nowNum-1;

	if(prevNum < 0){
		prevNum = 0;
	}

	if(prevNum==0){
		document.getElementById("galleryprev").style.display = "none";
	}else{
		document.getElementById("galleryprev").style.display = "block";
		document.getElementById("gallerynext").style.display = "block";
	}

	for(i=0;i<allCnt;i++){
		if(i==prevNum){
			document.getElementById("gallery"+i).style.display = "inline";
			i++;
			document.getElementById("gallery"+i).style.display = "inline";
			i++;
			document.getElementById("gallery"+i).style.display = "inline";
		}else{
			document.getElementById("gallery"+i).style.display = "none";
		}
	}

	nowNum = prevNum;
}