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;