function clickie() {
   if (document.all) {
      return false;
   }
}

function clickns(e) {
   if (document.layers||(document.getElementById&&!document.all)) {
      if (e.which==2 || e.which==3) {
         return false;
      }
   }
}

function trapclick() {
  if (document.layers) {
      document.captureEvents(Event.MOUSEDOWN);
      document.onmousedown=clickns;
  } else {
      document.onmouseup=clickns;
      document.oncontextmenu=clickie;
  }
}