function newImage(arg) {
  if (document.images) {
    rslt = new Image();
    rslt.src = arg;
    return rslt;
  }
}

function changeImages() {
  if (document.images && (preloadFlag == true)) {
    for (var i=0; i<changeImages.arguments.length; i+=2) {
      document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
    }
  }
}

var preloadFlag = false;
function preloadImages() {
  if (document.images) {
    menu01o = newImage("images/menu01o.gif");
    menu02o = newImage("images/menu02o.gif");
    menu03o = newImage("images/menu03o.gif");
    menu04o = newImage("images/menu04o.gif");
    menu05o = newImage("images/menu05o.gif");
    menu06o = newImage("images/menu06o.gif");
    menu07o = newImage("images/menu07o.gif");
    menu08o = newImage("images/menu08o.gif");
    menu09o = newImage("images/menu09o.gif");
    menu10o = newImage("images/menu10o.gif");
    menu11o = newImage("images/menu11o.gif");
    preloadFlag = true;
  }
}