var now   = new Date();
var year  = now.getYear();
if (year < 2000) year = year + 1900;

function window_open(pagina,titulo,ancho,largo,x,y)
{
 var Ventana= 'toolbar=0,location=0,directories=0,scrollbars=1,screenX='+x+',screenY='+y+',status=0,menubar=0,resizable=0,width='+ancho+',height='+largo;
 open(pagina,titulo,Ventana);
}