var finestra=null;

function NovaFinestra(url,nom,amplada,alcada)
{
	marge_esquerre=(screen.width)?(screen.width-amplada)/2:100;
	marge_superior=(screen.height)?(screen.height-alcada)/2:100;
	
	atributs='width='+amplada+',height='+alcada+',top='+marge_superior+',left='+marge_esquerre+',scrollbars=no,location=no,directories=no,status=no,menubar=no,toolbar=no,resizable=no';

	finestra=window.open(url,nom,atributs);
}