function click(e) 
{
  if (document.all) 
  {
    if ( event.button==2 || event.button==3 )
    {
      alert( "copyrighted - contact argo@agentura-argo.cz");
      return false;
    }
  }

  if (document.layers) 
  {
    if (e.which == 3) 
    {      
      alert( "copyrighted - contact argo@agentura-argo.cz");
      return false;
    }
  }
}

if  ( document.layers )
 {
  document.captureEvents(Event.MOUSEDOWN);
}

document.onmousedown=click;