折叠不起作用(Bootstrap 4)

Age*_*ges -2 javascript bootstrap-4

我在 bootstrap 4 中遇到崩溃问题。

我尝试通过 Javascript 来控制它,但它不起作用:

有人可以帮我吗?

Codepen https://codepen.io/Ages/pen/dempQm
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小智 6

请找到以下 Bootstrap 4 崩溃的代码

<!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
  <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>
  <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
</head>
<body>

<div class="container">
  <h2>Simple Collapsible</h2>
  <p>Click on the button to toggle between showing and hiding content.</p>
  <button type="button" class="btn btn-primary" data-toggle="collapse" data-target="#demo">Simple collapsible</button>
  <div id="demo" class="collapse">
    Lorem ipsum dolor sit amet, consectetur adipisicing elit,
    sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam,
    quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.
  </div>
</div>

</body>
</html>
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