Bootstrap5 下拉菜单
下拉菜单可以是单选下拉菜单，也可以是多选的下拉菜单。
单选下拉菜单：
多选下拉菜单：
在 Bootstrap5 中下拉菜单 <select> 元素可以使用 .form-select 类来渲染 :
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap5 实例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<div class="container mt-3">
<h2>下拉菜单</h2>
<p>在 Bootstrap5 中下拉菜单 select 元素可以使用 .form-select 类来渲染 :</p>
<form action="">
<label for="sel1" class="form-label">单选下拉菜单：</label>
<select class="form-select" id="sel1" name="sellist1">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
</select>
<br>
<label for="sel2" class="form-label">多选下拉菜单：</label>
<select multiple class="form-select" id="sel2" name="sellist2">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
<button type="submit" class="btn btn-primary mt-3">Submit</button>
</form>
</div>
</body>
</html>下拉菜单通过 .form-select-lg 或 .form-select-sm 类来修改大小：
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap5 实例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<div class="container mt-3">
<h2>下拉菜单</h2>
<p>下拉菜单通过 .form-select-lg 或 .form-select-sm 类来修改大小：</p>
<form action="">
<label for="sel1" class="form-label">大号下拉菜单：</label>
<select class="form-select form-select-lg" id="sel1" name="sellist1">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
</select>
<br>
<label for="sel2" class="form-label">正常下拉菜单：</label>
<select class="form-select" id="sel2" name="sellist2">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
<label for="sel3" class="form-label">小号下拉菜单：</label>
<select class="form-select form-select-sm" id="sel3" name="sellist3">
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
<button type="submit" class="btn btn-primary mt-3">Submit</button>
</form>
</div>
</body>
</html>效果如下图：
disabled 属性可以禁止下拉菜单被选择：
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap5 实例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<div class="container mt-3">
<h2>禁用下拉菜单</h2>
<p>disabled 属性可以禁止下拉菜单被选择：</p>
<form action="">
<label for="sel" class="form-label">禁用下拉菜单：</label>
<select class="form-select" id="sel" name="sellist" disabled>
<option>1</option>
<option>2</option>
<option>3</option>
<option>4</option>
<option>5</option>
</select>
<button type="submit" class="btn btn-primary mt-3">Submit</button>
</form>
</div>
</body>
</html>数据列表
Bootstrap 也可以通过 datalist 标签为 <input> 元素设置下拉菜单：
以下实例从列表中选择一个网站：
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap5 实例</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link href="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/css/bootstrap.min.css" rel="stylesheet">
<script src="https://cdn.staticfile.org/twitter-bootstrap/5.1.1/js/bootstrap.bundle.min.js"></script>
</head>
<body>
<div class="container mt-3">
<h2>数据列表</h2>
<form action="/action_page.php">
<label for="browser" class="form-label">选择你喜欢的网站：</label>
<input class="form-control" list="sites" name="site" id="site">
<datalist id="sites">
<option value="Google">
<option value="Runoob">
<option value="Taobao">
<option value="Wiki">
<option value="Zhihu">
</datalist>
<button type="submit" class="btn btn-primary mt-3">Submit</button>
</form>
</div>
</body>
</html>效果如下图：
