function popup(url, w, h) {
	wleft = (screen.width - w) / 2;
	wtop = (screen.height - h) / 2;
	newwindow=window.open(url,'name','scrollbars=yes,width='+w+',height='+h+',left='+wleft+',top='+wtop);
	if (window.focus) {newwindow.focus()}
	return false;
}