javascript - 如何创建下拉侧导航栏？

Question

当我单击下一步按钮时，如何激活/打开侧面导航栏中的下一个下拉菜单。如果我单击上一个按钮，如何在侧面导航栏中打开上一个下拉菜单。

Answer 1

  <!--index.html-->


 <div class="navbar">
         <div class="dropdown">
            <button class="dropbtn">Dropdown 
                <i class="fa fa-caret-down"></i>
        </button>
        <div class="dropdown-content">
            <a href="#">Link 1</a>
                <a href="#">Link 2</a>
            <a href="#">Link 3</a>
        </div>
      </div> 
    </div>

 <!--styles.css-->
body {
  font-family: Arial, Helvetica, sans-serif;
}

.navbar {
  overflow: hidden;
  background-color: #333;
}

.navbar a {
  float: left;
  font-size: 16px;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

.dropdown {
  float: left;
  overflow: hidden;
}

.dropdown .dropbtn {
  font-size: 16px;  
  border: none;
  outline: none;
  color: white;
  padding: 14px 16px;
  background-color: inherit;
  font-family: inherit;
  margin: 0;
}

.navbar a:hover, .dropdown:hover .dropbtn {
  background-color: red;
}

.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 {
  float: none;
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
  text-align: left;
}

.dropdown-content a:hover {
  background-color: #ddd;
}

.dropdown:hover .dropdown-content {
  display: block;
}