function check_admin(adresse){
  adresse = String(adresse);
  var _bedingung = /_modus=admin/; 
  if (adresse.match(_bedingung)){
    return true;
  }
  return false;
}

if ( (window.name == 'bau_oben') || parent.bau_oben || parent.top.bau_oben || check_admin(this.location)){
  
}
else{
  parent.top.location = 'http://www.abc-rlp.de/?' + this.location;
}