使用方式

<link rel="stylesheet" href="/components/style/dropdown.css" type="text/css" />
<script defer src="/components/js/dropdown.js" type="text/javascript"></script>

<div class="st_dropdown">
  <span>name</span>
  <i class="stIconFont icon-xiala-solid"></i>
  <ul class="st_dropdown_menu">
    <li>选择1</li>
    <li>选择2</li>
  </ul>
</div>