引导下拉菜单不起作用（尽管在 bootstrap.js 之前包含 jquery）答案

【问题标题】：bootstrap dropdown not working (although included jquery before bootstrap.js)引导下拉菜单不起作用（尽管在 bootstrap.js 之前包含 jquery）
【发布时间】：2018-10-04 08:08:00
【问题描述】：

我正在尝试使引导下拉菜单工作。但它顽固地不起作用。我已经抓取了 stackoverflow 问题，并在 bootstrap.js 之前包含了最新的 bootstrap.js 和 jquery 加载，并使用了最新的 HTML 版本。下拉菜单仍然不起作用。 jsfiddle 包含在下面。

<!--Dropdown primary-->
 <div class="dropdown" id="myDropdown">

     <!--Trigger-->
     <button class="btn btn-primary dropdown-toggle" type="button" id="dropdownMenu1" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">Dropdown primary</button>

     <!--Menu-->
     <div class="dropdown-menu dropdown-primary">
         <a class="dropdown-item" href="#">Action</a>
         <a class="dropdown-item" href="#">Another action</a>
         <a class="dropdown-item" href="#">Something else here</a>
         <a class="dropdown-item" href="#">Something else here</a>
     </div>
 </div>
 <!--/Dropdown primary-->

http://jsfiddle.net/675mhy0a/6/

【问题讨论】：

您是否在控制台中查看它正在输出错误：dropdown.js:155 Uncaught TypeError: Bootstrap dropdown require Popper.js
@Yousef_Shamshoum 仍然错误jsfiddle.net/675mhy0a/8

标签： jquery twitter-bootstrap

【解决方案1】：

需要引导下拉菜单 Popper.js https://getbootstrap.com/

<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">

<div class="dropdown">
  <button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    Dropdown button
  </button>
  <div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
    <a class="dropdown-item" href="#">Action</a>
    <a class="dropdown-item" href="#">Another action</a>
    <a class="dropdown-item" href="#">Something else here</a>
  </div>
</div>


<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>

http://jsfiddle.net/675mhy0a/9/

【讨论】：