function clickIE4() {
      if (event.button == 2){
        return false;
      }
    }

    function clickNS4(e) {
      if (document.layers||document.getElementById&&!document.all) {
        if (e.which == 2||e.which == 3) {
          return false;
        }
      }
    }

    if (document.layers) {
      document.captureEvents(Event.MOUSEDOWN);
      document.onmousedown = clickNS4;
    }
    else if (document.all &&! document.getElementById) {
      document.onmousedown = clickIE4;
    }
     
    document.oncontextmenu = new Function("return false")