if (window.Event)
  document.captureEvents(Event.MOUSEUP);

function nocontextmenu() {
  event.cancelBubble = true, event.returnValue = false;

  return false;
} 

function norightclick(e) {
  if (window.Event) {
    if (e.which == 2 || e.which == 3) return false;
  }
  else if (event.button == 2 || event.button == 3) {
    event.cancelBubble = true, event.returnValue = false;
    return false;
  }
}

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

document.oncontextmenu = nocontextmenu;
document.onmousedown = norightclick;
document.onmouseup = norightclick;
//-->