그누보드 5.3 모바일 홈페이지 메뉴 Jquery 문의

<ul id="gnb_1dul">
                            <li class="gnb_1dli">
                    <a href="#" target="_self" class="gnb_1da">메뉴 1</a>
                    <button type="button" class="btn_gnb_op">하위분류</button><ul class="gnb_2dul" style="overflow: hidden; display: none;">
                        <li class="gnb_2dli"><a href="/bbs/content.php?co_id=intro001" target="_self" class="gnb_2da"><span></span>컨텐츠 1</a></li>
                                            <li class="gnb_2dli"><a href="/bbs/board.php?bo_table=board" target="_self" class="gnb_2da"><span></span>게시판 1</a></li>
                    </ul>
                </li>
                            <li class="gnb_1dli">
                    <a href="#" target="_self" class="gnb_1da">메뉴 2</a>
                    <button type="button" class="btn_gnb_op">하위분류</button><ul class="gnb_2dul">
                        <li class="gnb_2dli"><a href="/bbs/content.php?co_id=intro001" target="_self" class="gnb_2da"><span></span>컨텐츠 2</a></li>
                                            <li class="gnb_2dli"><a href="/bbs/board.php?bo_table=board2" target="_self" class="gnb_2da"><span></span>게시판 2</a></li>
                    </ul>
                </li>
                            <li class="gnb_1dli">
                    <a href="#" target="_self" class="gnb_1da">메뉴 3</a>
                    <button type="button" class="btn_gnb_op">하위분류</button><ul class="gnb_2dul">
                        <li class="gnb_2dli"><a href="/bbs/content.php?co_id=intro001" target="_self" class="gnb_2da"><span></span>컨텐츠 3</a></li>
                                            <li class="gnb_2dli"><a href="/bbs/board.php?bo_table=board3" target="_self" class="gnb_2da"><span></span>게시판 3</a></li>
                    </ul>
                </li>
                            <li class="gnb_1dli">
                    <a href="#" target="_self" class="gnb_1da">메뉴 4</a>
                    <button type="button" class="btn_gnb_op">하위분류</button><ul class="gnb_2dul">
                        <li class="gnb_2dli"><a href="/bbs/content.php?co_id=intro001" target="_self" class="gnb_2da"><span></span>컨텐츠 4</a></li>
                                            <li class="gnb_2dli"><a href="/bbs/board.php?bo_table=board4" target="_self" class="gnb_2da"><span></span>게시판 4</a></li>
                    </ul>
                </li>
                            <li class="gnb_1dli">
                    <a href="#" target="_self" class="gnb_1da">메뉴 5</a>
                    <button type="button" class="btn_gnb_op">하위분류</button><ul class="gnb_2dul">
                        <li class="gnb_2dli"><a href="/bbs/content.php?co_id=intro001" target="_self" class="gnb_2da"><span></span>컨텐츠 5</a></li>
                                            <li class="gnb_2dli"><a href="/bbs/board.php?bo_table=board5" target="_self" class="gnb_2da"><span></span>갤러리 5</a></li>
                    </ul>
                </li>
                        </ul>

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