function Pcent(nome, titolo, lar, alt, feat){
var wdt = screen.width;
var hgt = screen.height;
var x = Math.round( (wdt / 2) - (lar / 2) );
var y = Math.round( (hgt / 2) - (alt / 2) );
window.open(nome, titolo, 'width=' + lar + ',height=' + alt + ',left=' + x + ',screenX=' + x + ',top=' + 150 + ',screenY=' + 150 + ',' + feat);
}