popupw = null;
function popup(w,h) {
	if(!popupw || popupw.closed)
		popupw = window.open('about:blank','popup','scrollbars=yes,toolbar=no,menubar=no,location=no,directories=no,resize=yes,width='+(w!=undefined?w:'400')+',height='+(h!=undefined?h:'300'));
	else
		popupw.focus();
}