var upID = null;


function popup (div_id) {
	if (upID!=null)
	{
		document.getElementById(div_id).style.zIndex = 0;
		document.getElementById(upID).style.visibility ='hidden';
	}
	document.getElementById(div_id).style.visibility ='visible';
	document.getElementById(div_id).style.zIndex = 10;
	upID = div_id;
}

function close_popup (div_id) {
	document.getElementById(div_id).style.visibility ='hidden';
	document.getElementById(div_id).style.zIndex = 0;
	upID=null;
}