if(document.images) {
    cat = new Array(); 
    cat[21] = new Image();
    cat[21].src = "/elearning/images/navigation/database_button.jpg";
    cat[22] = new Image();
    cat[22].src = "/elearning/images/navigation/database_rolo.jpg";
    cat[23] = new Image();
    cat[23].src = "/elearning/images/navigation/compfund_button.jpg";
    cat[24] = new Image();
    cat[24].src = "/elearning/images/navigation/compfund_rolo.jpg";
    cat[25] = new Image();
    cat[25].src = "/elearning/images/navigation/k12_button.jpg";
    cat[26] = new Image();
    cat[26].src = "/elearning/images/navigation/k12_rolo.jpg";
    cat[27] = new Image();
    cat[27].src = "/elearning/images/navigation/it_button.jpg";
    cat[28] = new Image();
    cat[28].src = "/elearning/images/navigation/it_rolo.jpg";
    cat[29] = new Image();
    cat[29].src = "/elearning/images/navigation/office_button.jpg";
    cat[30] = new Image();
    cat[30].src = "/elearning/images/navigation/office_rolo.jpg";
    cat[31] = new Image();
    cat[31].src = "/elearning/images/navigation/personal_button.jpg";
    cat[32] = new Image();
    cat[32].src = "/elearning/images/navigation/personal_rolo.jpg";
    cat[33] = new Image();
    cat[33].src = "/elearning/images/navigation/vocational_button.jpg";
    cat[34] = new Image();
    cat[34].src = "/elearning/images/navigation/vocational_rolo.jpg";
    cat[35] = new Image();
    cat[35].src = "/elearning/images/navigation/web_button.jpg";
    cat[36] = new Image();
    cat[36].src = "/elearning/images/navigation/web_rolo.jpg";
    }
    function swapper(from,to) {
    if(document.images) {
    document.images[from].src = cat[to].src;
    }
  }