js+jq
by qwerew0
HTML
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.6.3/jquery.min.js"></script>
<ul class="gnb">
<li>
<a href="#">회사소개</a>
<ul class="sub">
<li><a href="#">submenu1</a></li>
<li><a href="#">submenu2</a></li>
<li><a href="#">submenu3</a></li>
<li><a href="#">submenu4</a></li>
</ul>
</li>
</ul>
JavaScript
$(function(){
$('.sub').css('display','none');
$('.gnb>li>a').click(function(){
var kkk = $(this).next('.sub').css('display');
// 클릭한것의 다음에 있는 .sub의 display 상태를 물어봄
if(kkk=='none'){
$(this).next().slideDown();
}else{
$(this).next().slideUp();
}
});
});