function popupwindow(target_url,set_width,set_height)
{
	if (!set_width) set_width='450';
	if (!set_height) set_height='300';
	myWindow = window.open(target_url, 'popup', 'fullscreen=no,toolbar=no,status=no,menubar=no,scrollbars=yes,resizable=yes,directories=no,location=no,width='+set_width+',height='+set_height);
        myWindow.focus();
}