function change_img(img1,img2,lang,ls) {
  if (document.images) {
    active = new Image ();
    normal = new Image ();
    active.src = '/' + ls + '/' + lang + '/image/h/'+ img2 + '.gif';
    normal.src = '/' + ls + '/' + lang + '/image/h/'+ img1 + '.gif';
    if (img1 != img2) {
      document.images[img1].src = active.src;
    } else {
      document.images[img1].src = normal.src;
    }
  }
}