如何制作可点击的父链接折叠菜单

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

/* 隐藏子菜单 */
.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;
}

/* 显示子菜单 */
.dropdown:hover .dropdown-content {
  display: block;
}

/* 鼠标悬停样式 */
.dropdown-content a:hover {
  background-color: #f1f1f1;
}

/* 父链接样式 */
.dropbtn {
  background-color: #4CAF50;
  color: white;
  padding: 10px;
  font-size: 16px;
  border: none;
  cursor: pointer;
}

/* 下拉箭头样式 */
.fa-caret-down {
  margin-left: 5px;
}

// 获取父链接按钮和子菜单
var dropdown = document.getElementsByClassName("dropdown");
var i;

// 遍历所有父链接
for (i = 0; i < dropdown.length; i++) {
  dropdown[i].addEventListener("click", function() {
    this.classList.toggle("active");
    var dropdownContent = this.nextElementSibling;
    if (dropdownContent.style.display === "block") {
      dropdownContent.style.display = "none";
    } else {
      dropdownContent.style.display = "block";
    }
  });
}