jQuery insertBefore

<div class="todayBg">
    <dl>
 <img src="/skin/f_modern/images/module/today_view_up_btn.gif" alt="" class="prev" stlye="cursor:pointer">
  <dd><a href="?act=shop.goods_view&amp;GS=2&amp;GC=GD00"><img src="/data/goods/0/2/pro01.view.jpg" alt="상품이미지"></a></dd>
  <dd><a href="?act=shop.goods_view&amp;GS=4&amp;GC=GD00"><img src="/data/goods/0/4/pro03.view.jpg" alt="상품이미지"></a></dd>
  <dd><a href="?act=shop.goods_view&amp;GS=5&amp;GC=GD00"><img src="/data/goods/0/5/pro04.view.jpg" alt="상품이미지"></a></dd>
  <dd style="display:none;"><a href="?act=shop.goods_view&amp;GS=7&amp;GC=GD03"><img src="/data/goods/0/7/pro05.view.jpg" alt="상품이미지"></a></dd>
  <dd style="display:none;"><a href="?act=shop.goods_view&amp;GS=8&amp;GC=GD01"><img src="/data/goods/0/8/pro06.view.jpg" alt="상품이미지"></a></dd>    
 <img src="/skin/f_modern/images/module/today_view_down_btn.gif" alt="" class="next" stlye="cursor:pointer">
    </dl>
</div>

 function move(cmd ){
  if(cmd == "prev"){
   $(".todayBg dd:last").show();
   $(".todayBg dd:eq(2)").hide();
   $(".todayBg dd:last").insertBefore(".todayBg dd:eq(0)");

  }else{

   $(".todayBg dd:eq(0)").hide();
   $(".todayBg dd:eq(3)").show();

   $(".todayBg dd:eq(0)").insertBefore(".todayBg img:last");
  }

 }
 $(document).ready(function(){

  $(".todayBg .prev").click(function(){
   move("prev");
  });

  $(".todayBg .next").click(function(){
   move("next");
  });
 });