擅长:python、mysql、java
<p>因此,我还研究了您的代码和w3schools示例。好像是这样</p>
^{1}$
<p>打得不好。你不想用的原因是什么</p>
^{pr2}$
<p>因为当我替换CSS链接时,它在你的代码中运行得很好。希望对你有帮助。在</p>
<p>这是您的代码:</p>
<pre><code><!DOCTYPE html>
<html lang="en">
<head>
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<! <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css"> >
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://code.jquery.com/jquery-3.2.1.slim.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.11.0/umd/popper.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/js/bootstrap.min.js"></script>
</head>
<body>
<div class="container">
<h2>Basic Panel</h2>
<div class="panel panel-default">
<div class="panel-body">A Basic Panel</div>
</div>
</div>
</body>
</html>
</code></pre>