如何实现位置下拉菜单？

<div class="dropdown">
  <button class="dropbtn">选择位置</button>
  <div class="dropdown-content">
    <a href="#">北京</a>
    <a href="#">上海</a>
    <a href="#">广州</a>
    <!-- 其他位置选项 -->
  </div>
</div>

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

.dropbtn {
  background-color: #4CAF50;
  color: white;
  padding: 10px;
  font-size: 16px;
  border: none;
  cursor: pointer;
}

.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-content a:hover {
  background-color: #f1f1f1;
}

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

// 获取下拉菜单容器
var dropdown = document.getElementsByClassName("dropdown")[0];

// 获取下拉菜单内容
var dropdownContent = dropdown.getElementsByClassName("dropdown-content")[0];

// 监听点击事件，隐藏下拉菜单
document.addEventListener("click", function(event) {
  if (!dropdown.contains(event.target)) {
    dropdownContent.style.display = "none";
  }
});

// 监听按钮点击事件，显示/隐藏下拉菜单
dropdown.getElementsByClassName("dropbtn")[0].addEventListener("click", function() {
  dropdownContent.style.display = (dropdownContent.style.display === "block") ? "none" : "block";
});