function apri(url) {
var w = 800;
var h = 600;
var l = Math.floor((screen.width-w)/2);
var t = Math.floor((screen.height-h)/2);
newin = window.open(url,'titolo','scrollbars=no,resizable=yes, width=' + w + ',height=' + h + ',top=' + t + ',left=' + l +',status=no,location=no,toolbar=no');
pagina.document.open ();
pagina.document.write
('Ingrandimento
');
pagina.document.close();
pagina.focus();
}