function popup (tamanyX, tamanyY, adre, nom, posX, posY, attr) {
				var x=(screen.width-tamanyX) * posX / 100;
                var y=(screen.height-tamanyY) * posY / 100;
                if (attr=="") {attr='resizable=0,toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0'}
                finestra=open(adre,nom,attr+',width='+tamanyX+',height='+tamanyY+',left='+x+',top='+y+',screenX='+x+',screenY='+y+'');
}

function credits(pagina) {
	popup (398,400,pagina,'wcredits',50,50,'');
}