JSFiddle - React, Tailwind, and code Playground

by wimp9487

HTML

<nav>
   <ul class="nav">
      <li><a href="#">首頁</a></li>
      <li><a href="#">全部商品</a></li>
      <li><a href="#">全部品牌</a></li>
      <li class="about-us">關於我們
         <ul class="dropdown">
            <li><a href="#">團隊介紹</a></li>
            <li><a href="#">企業宗旨</a></li>
            <li><a href="#">創業故事</a></li>      
         </ul>
      </li>
   </ul>
</nav>

CSS

* {
    box-sizing: border-box;
    list-style: none;
    text-decoration: none;
    color: #777;
}
nav {
  height: 100%;
}
nav .nav {
  display: flex;
  background-color: #D3D3D3;
}
nav .nav li {
  position: relative;
  flex: 1 0;
  height: 60px;
  font-size: 14px;
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
}
.about-us ul{
  visibility: hidden;
  position: absolute;
  flex-direction: column;
  top: 100%;
  left: -40px;
  right: 0;
  color: #333;
  background-color: #e5e4ea;

}
.about-us.open ul{
  visibility: visible;
}

JavaScript

const aboutUs = document.querySelector(".about-us");
const visible = () => {
   aboutUs.classList.toggle('open');
};
aboutUs.onclick = visible;