W3School TIY Editor

<!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%;
}

.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; /* 在这个例子中用于启用滚动 */
}
</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>请滚动此页面以查看效果</h2>
  <h2>导航栏将在页面滚动时固定在页面顶部</h2>

</body>
</html>