var WindowObjectReference = null;
function AbrirMapa(url)
{
  if(WindowObjectReference == null || WindowObjectReference.closed)
  {
    WindowObjectReference = window.open(url,
   "Mapa", "top=0,left=0,width=790,height=580,resizable=yes,scrollbars=yes,status=no");
  }
  else
  {
    WindowObjectReference.focus();
  };
}