function right(e) {
  if (navigator.appName == 'Netscape' && (e.which == 3 || e.which == 2)) {
    return false;
  }
  return true;
}
document.onmousedown=right;
if (document.layers) {
  window.captureEvents(Event.MOUSEDOWN);
}
window.onmousedown=right;

function left(e) {
  if (navigator.appName == 'Netscape' && (e.which == 3 || e.which == 2)) {
    return false;
  }
  return true;
}
document.onmousedown=left;
if (document.layers) {
  window.captureEvents(Event.MOUSEDOWN);
}
window.onmousedown=left;