function nwin(page, x, y)
{
 sx = screen.availWidth;
 sy = screen.availHeight;
 px = (sx/2)-(x/2);
 py = (sy/2)-(y/2);
 window.open(page,'','scrollbars=no,top='+py+',left='+px+',width='+x+',height='+y+', status=no');
 return;
}