function MM_openBrWindow(theURL,winName,features) { //v2.0

  posicion = features+ ",left=40,top=40";
  if (! newwin)
  {
        //No existe

  	newwin=window.open(theURL,winName,posicion);
  }
  else
  {
      //existe
      newwin.close();
  	newwin=window.open(theURL,winName,posicion);
  }

}

function cerrarPopUp()
{
 	if(newwin) newwin.close();
}