function PopupCentrata(width,height,file,scrollbars,nome_pagina) {
   var w = width;
   var h = height;
   var l = Math.floor((screen.width-w)/2);
   var t = Math.floor((screen.height-h)/2);
   var s = scrollbars;
   window.open(file, nome_pagina, "width=" + w + ",height=" + h + ",top=" + t + ",left=" + l + ",scrollbars=" + s + "");
 }