jsp导航栏下拉菜单

<nav>
  <ul>
    <li><a href="home.jsp">首页</a></li>
    <li class="dropdown">
      <a href="#" class="dropbtn">产品</a>
      <div class="dropdown-content">
        <a href="products/electronics.jsp">电子产品</a>
        <a href="products/clothing.jsp">服装</a>
        <a href="products/books.jsp">书籍</a>
      </div>
    </li>
    <li><a href="contact.jsp">联系我们</a></li>
  </ul>
</nav>

<style>
.dropdown {
  position: relative;
  display: inline-block;
}

.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
  z-index: 1;
}

.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
}

.dropdown:hover .dropdown-content {
  display: block;
}
</style>