<!DOCTYPE html>
<html lang="en">
<head>
<title>Bootstrap 示例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="https://www.w3schools.cn/lib/bootstrap/5.1.3/css/bootstrap.min.css" rel="stylesheet">
<script src="https://www.w3schools.cn/lib/bootstrap/5.1.3/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<div class="container mt-3">
<h2>屏幕阅读器</h2>
<p>使用 .sr-only 类在所有设备上隐藏元素，屏幕阅读器除外：</p>
<span class="visually-hidden">除了屏幕阅读器，我将隐藏在所有屏幕上。</span>
</div>
</body>
</html>