var n = document.getElementById("cfondo");
var cancho=500;
var calto=440;
if (navigator.appName=="Netscape" || navigator.appName=="Opera")
{
  var pancho=window.innerWidth;
  var palto=window.innerHeight;
} else {
  var pancho=document.body.clientWidth;
  var palto=document.body.clientHeight;
}
var cizq=(pancho-cancho)/2;
if (cizq < 0)
   cizq = 0;
var carr=(palto-calto)/2;
if (carr < 0)
   carr = 0;
n.style["left"] = cizq;
n.style["top"] = carr;


function ver (foto){
  var ancho=screen.width;
  var alto=screen.height;
  var w=500;
  var h=440;
  
  ancho=(ancho-w)/2;
  alto=(alto-h)/2;

  if (fotowin && fotowin.open && !fotowin.closed) fotowin.close();
  fotowin = window.open('foto.html','','toolbar=no,location=no,directories=no,status=no,menubar=no,scrollbars=no,resizable=no,width='+w+',height='+h+',top='+alto+',left='+ancho);
  actual = foto;
}