function openPopup( pageURI, windowName, popupWidth, popupHeight )
{
	var winl = ( screen.width - popupWidth )/2;
	var wint = ( screen.height - popupHeight )/2;
	window.open( pageURI, windowName,
		'toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=yes,copyhistory=no,' +
		'width=' + popupWidth + ',height=' + popupHeight + ' top='+wint+',left='+winl+''
	)	
}