function right(e) 
{
  if (navigator.appName == 'Netscape' && (e.which == 3 || e.which == 2))
    return false;
  else if (navigator.appName == 'Microsoft Internet Explorer' 
    && (event.button == 2 || event.button == 3)) 
  {
    alert("Copyright 2008 RPPS, Bratislava");
    return false;
  }
  return true;
}

document.onmousedown=right;
document.onmouseup=right;
if (document.layers) window.captureEvents(Event.MOUSEDOWN);
if (document.layers) window.captureEvents(Event.MOUSEUP);
window.onmousedown=right;
window.onmouseup=right;