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;