function segnala(pagina,nome){
  w = 440;
  h = 320;
  x = Math.ceil( (window.screen.width  - w) / 2 );
  y = Math.ceil( (window.screen.height  - h) / 2 );
  tl = 'top='+y+',left='+x+',';
  aa = window. open(pagina,nome,tl+'toolbar=no,status=no,scrollbars=no,resizable=no,width='+w+',height='+h);
  aa.focus();
}