我有一个最简单的下拉列表，它根据选择的选项将表单发送到服务器：
<html lang="en">
<body>
<form name="add" method="post">
<select onchange="this.form.submit()" name=provider>
<option value=first>first</option>
<option value=second>second</option>
</select>
</form>
</body>
</html>
现在我想使用bootstrap来实现这一点，但我完全不知道如何实现同样的功能。有什么想法吗？
带有引导程序的完整html：
<!doctype html>
<html lang="en">
<head>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/bootstrap@4.3.1/dist/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
</head>
<body>
<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown button
</button>
<div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
<a class="dropdown-item" href="#">Action</a>
<a class="dropdown-item" href="#">Another action</a>
<a class="dropdown-item" href="#">Something else here</a>
</div>
</div>
<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/popper.js@1.14.7/dist/umd/popper.min.js" integrity="sha384-UO2eT0CpHqdSJQ6hJty5KVphtPhzWj9WO1clHTMGa3JDZwrnQq4sF86dIHNDz0W1" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/bootstrap@4.3.1/dist/js/bootstrap.min.js" integrity="sha384-JjSmVgyd0p3pXB1rRibZUAYoIIy6OrQ6VrjIEaFf/nJGzIxFDsf4x0xIM+B07jRM" crossorigin="anonymous"></script>
</body>
</html>
为了保持请求逻辑并发送标准POST请求，可以只隐藏一个类型为<form>的输入，并动态更新其值。该值可以从<a>链路的数据属性中存储和提取，这里有一个简单的实现：
<div class="dropdown">
<button class="btn btn-secondary dropdown-toggle" type="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
Dropdown button
</button>
<div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
<a class="dropdown-item" data-value="first" href="#">Action</a>
<a class="dropdown-item" data-value="second" href="#">Another action</a>
</div>
<form class="d-none" name="add" method="post">
<input type="hidden" name="provider" value="">
</form>
</div>
还有一些简单的jQuery代码：
$('.dropdown-menu .dropdown-item').on('click', function() {
var element = $(this);
var form = $('form', element.closest('.dropdown'));
$('input[name="provider"]', form).val(element.data('value'))
form.submit();
});