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

function custom_get_element_by_id(id) {
  if (document.all) {
    return document.all[id];
  }

  return document.getElementById(id);
}

function change_element_css_class(id, css_class_name) {
  e = custom_get_element_by_id(id);
  e.className = css_class_name;
}

function preloadImages() {
  pre_menu_bullet_1 = custom_new_image('imgs/nav_bullets/main_nav_black.gif');
  pre_menu_bullet_2 = custom_new_image('imgs/nav_bullets/main_nav_grey_small.gif');
  pre_menu_bullet_3 = custom_new_image('imgs/nav_bullets/main_nav_red.gif');
  pre_menu_bullet_4 = custom_new_image('imgs/nav_bullets/main_nav_red_small.gif');
  pre_menu_bullet_5 = custom_new_image('imgs/nav_bullets/top_nav_black.gif');
  pre_menu_bullet_6 = custom_new_image('imgs/nav_bullets/top_nav_red.gif');
}