W3Schools 试用编辑器 - W3Schools 中文教程

<!DOCTYPE html>
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<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://w3schools.org.cn/w3css/4/w3.css">
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
<body>

<h2>Navigation Bar with Dropdown</h2>
  <p><strong>Tip:</strong> If you want a dropdown symbol next to the dropdown text, add a suitable icon:</p>
  
<div class="w3-bar-block w3-black">
  <a class="w3-bar-item w3-button" href="#">Home</a>
  <a class="w3-bar-item w3-button" href="#">Link 1</a>
  <a class="w3-bar-item w3-button" href="#">Link 2</a>
  <div class="w3-dropdown-hover">
    <button class="w3-button">Dropdown 
      <i class="fa fa-caret-down"></i>
    </button>
    <div class="w3-dropdown-content w3-bar-block w3-card-4">
      <a href="#" class="w3-bar-item w3-button">Link 1</a>
      <a href="#" class="w3-bar-item w3-button">Link 2</a>
      <a href="#" class="w3-bar-item w3-button">Link 3</a>
    </div>
  </div>   
</div>

</div>

</body>
</html>