var itemFlag = "pic1";
function hideItem(itemId){
	var itemTag = document.getElementById(itemId);	
	itemTag.style.display = "none";	
}
function showItem(itemId){
	if (itemId != itemFlag){
		var itemTag = document.getElementById(itemId);	
		itemTag.style.display = "";	
		hideItem(itemFlag);
		itemFlag = itemId;
	}
}
function showNextItem(){
	var itemId = itemFlag.substr(0,3);	
	var itemNum = Number(itemFlag.substr(3,2))+1;
	if (itemNum > 104){ itemNum = 1;}
		itemId = itemId.concat(itemNum.toString());
	showItem(itemId);
}
function showPrevItem(){
	var itemId = itemFlag.substr(0,3);	
	var itemNum = Number(itemFlag.substr(3,2))-1;
	if (itemNum < 1){ itemNum = 26;}
		itemId = itemId.concat(itemNum.toString());
	showItem(itemId);
}