제이쿼리.. 메뉴 슬라이드 질문있습니다! 채택완료

<script type="text/javascript">

$(document).ready(function(){

    var nav_ul = $('#nav > li > ul'),
        nav_a = $('#nav > li > a');

    //nav_ul.hide();


    nav_a.click(function(e){
        var index = $(nav_a).index(this); //인덱스값


        e.preventDefault();
        console.log(index);

        if(!$(this).hasClass("open")) {
            // hide any open menus and remove all other classes
            nav_a.removeClass("open");
            nav_ul.filter(':visible').slideUp('normal');
            $(this).addClass('open').next().stop(true,true).slideDown('normal');

            // open our new menu and add the open class
            $(this).next("ul").slideDown('normal');
            $(this).addClass("open");

        }else{
            $(this).removeClass('open');
            $(this).next().stop(true,true).slideUp('normal');
        }
    });
    $('a[href$="$_GET['bo_table']?>"]').fisrt().click();
});

script>


 <div>
  <nav>
    <ul id="nav">
      <li><a href="G5_BBS_URL ?>/board.php?bo_table=individuality">PROFILEa>
        <ul>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=individuality">INDIVIDUALITYa>li>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=artist">ARTISTa>li>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=professional">PROFESSIONALa>li>

        ul>
      li>
      <li><a href="G5_BBS_URL ?>/board.php?bo_table=lifestyle">LIFESTYLEa>
         <ul>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=lifestyle">LIFESTYLEa>li>
        ul>
      li>
      <li><a href="G5_BBS_URL ?>/board.php?bo_table=wedding">WEDDINGa>
         <ul>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=wedding">WEDDINGa>li>
        ul>
       
      li>
      <li><a href="#">MAKE-UPa>
       <ul>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=makeup">MAKE-UPa>li>
        ul>
        
      li>
      <li><a href="#">ABOUTa>
        <ul>
          <li><a href="/sub/service.php">SERVICEa>li>
          <li><a href="/sub/map.php">MAPa>li>
      ul>
      li>
      <li><a href="#">BOARDa>
        <ul>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=qna">Q&Aa>li>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=select">SELECTa>li>
        ul>
      li>
      
      <li><a href="#">MODELa>
        <ul>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=model_profile">모델프로필a>li>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=model_applicant">모델지원a>li>
        ul>
      li>
      <li><a href="#">COOPERATIONa>
      <ul>
          <li><a href="G5_BBS_URL ?>/board.php?bo_table=cooperation">COOPERATIONa>li>
        ul>
      
      
       li>
    ul>
  nav>
div>

코딩이 이렇게 되어있습니다..ㅠㅠ 
지금 제가 하고싶은게.. 해당게시판을 누르고 그 게시판으로 페이지 이동이 되었을때
메뉴가 열려있는 (sildeDown) 상태로 유지되게 하고싶습니다ㅠㅠ
index값으로 하는거 인거 같아서 이렇게저렇게 해보고 bo_table 값으로도 해보고 했는데 잘 안되네요..ㅠㅠ
도움 좀 주세요 고수님들..ㅠㅠ