margin-bottom无法正常工作并显示间隙html和css

编程问答 2022-08-12

问题描述

<!DOCTYPE html>
<html>

<head>
  <Meta name="viewport" content="width=device-width,initial-scale=1">
  <style>
    body {
      margin: 0;
    }
    
    .navbar {
      overflow: hidden;
      background-color: #333;
      position: fixed;
      top: 0;
      width: 100%;
      margin-bottom: 200px;
    }
    
    .navbar a {
      float: left;
      display: block;
      color: #f2f2f2;
      text-align: center;
      padding: 14px 16px;
      text-decoration: none;
      font-size: 17px;
    }
    
    .navbar a:hover {
      background: #ddd;
      color: black;
    }
    
    .main {
      padding: 16px;
      margin-top: 30px;
      height: 1500px;
      /* Used in this example to enable scrolling */
    }
  </style>
</head>

<body>

  <div class="navbar">
    <a href="#home">Home</a>
    <a href="#news">News</a>
    <a href="#contact">Contact</a>
  </div>

  <div class="main">
    <h1>Fixed Top Menu</h1>
    <h2>Scroll this page to see the effect</h2>
    <h2>The navigation bar will stay at the top of the page while scrolling</h2>

    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
  </div>

</body>

</html>

在 .navbar 选择器中，我添加了margin-bottom：200px;为什么它没有显示任何效果。为什么不在导航栏和其下方的内容之间放置200px的间距。 我试图显示它们之间的差距，并尝试从下至上。只想知道为什么它不起作用。 我提供了以下代码。

解决方法

因为您指定了position: fixed规则。我用position: sticky规则代替了您。您的margin-bottom现在可以正常工作。

<!DOCTYPE html>
<html>

<head>
  <meta name="viewport" content="width=device-width,initial-scale=1">
  <style>
    body {
      margin: 0;
    }
    
    .navbar {
      overflow: hidden;
      background-color: #333;
      /*position: fixed;*/
      position: sticky;
      top: 0;
      width: 100%;
      margin-bottom: 200px;
    }
    
    .navbar a {
      float: left;
      display: block;
      color: #f2f2f2;
      text-align: center;
      padding: 14px 16px;
      text-decoration: none;
      font-size: 17px;
    }
    
    .navbar a:hover {
      background: #ddd;
      color: black;
    }
    
    .main {
      padding: 16px;
      margin-top: 30px;
      height: 1500px;
      /* Used in this example to enable scrolling */
    }
  </style>
</head>

<body>

  <div class="navbar">
    <a href="#home">Home</a>
    <a href="#news">News</a>
    <a href="#contact">Contact</a>
  </div>

  <div class="main">
    <h1>Fixed Top Menu</h1>
    <h2>Scroll this page to see the effect</h2>
    <h2>The navigation bar will stay at the top of the page while scrolling</h2>

    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
    <p>Some text some text some text some text..</p>
  </div>

</body>

</html>

headerhtmlmargin