// open popup window
function popupWindow(url,winName,w,h) {
	var leftPos = (screen.width) ? (screen.width - w) / 2 : 0;
	var topPos = (screen.height) ? (screen.height - h) / 2 : 0;
	var features = 'width='+w+',height='+h+',left='+leftPos+',top='+topPos+',toolbar=0,location=0,directories=0,status=1,menubar=0,scrollbars=1,resizable=0';
	winName = window.open(url,winName,features);
	if (window.focus) { winName.focus(); }
}