var currentIdx = null;
function select(idx){	
	document["mn" + idx].src = "images/left_arrow_sel.gif";
}
function unselect(idx){	
	if (idx!=currentIdx) document["mn" + idx].src = "images/left_arrow_uns.gif";
}
function selectMenuItem(idx){
	if (idx==-1 || idx==0){
		currentIdx = null
	}
	else{
		currentIdx = idx;
		select(idx);
	}
}