在post.php中插入

  <script src="https://cdn.imsun.org/highlight/prism.js"></script>
  <link rel="stylesheet" href="https://cdn.imsun.org/highlight/prism.css"  />
  <script>
  document.addEventListener('DOMContentLoaded', function () {
    var defaultLanguage = 'javascript'; 
    document.querySelectorAll('pre code').forEach(function (block) {
      if (!block.classList.length) {
        block.classList.add('language-' + defaultLanguage);
      }
    });
    Prism.highlightAll();
  });
  </script>

即可实现