Bootstrap输入组中的Segment按钮下拉列表
要在输入组中细分按钮下拉菜单，请使用与下拉按钮相同的常规样式，但要在下拉菜单中添加主要操作，如以下示例所示：
示例
<!DOCTYPE html>
<html>
<head>
<title>Bootstrap Example</title>
<link href = "/bootstrap/css/bootstrap.min.css" rel = "stylesheet">
<script src = "/scripts/jquery.min.js"></script>
<script src = "/bootstrap/js/bootstrap.min.js"></script>
</head>
<body>
<div style = "padding: 100px 100px 10px; background: red;">
<form class = "bs-example bs-example-form" role = "form">
<div class = "row">
<div class = "col-lg-6">
<div class = "input-group">
<div class = "input-group-btn">
<button type = "button" class = "btn btn-default" tabindex = "-1">Subject</button>
<button type = "button" class = "btn btn-default dropdown-toggle"
data-toggle = "dropdown" tabindex = "-1">
<span class = "caret"></span>
<span class = "sr-only">Toggle Dropdown</span>
</button>
<ul class = "dropdown-menu">
<li><a href = "#">Maths</a></li>
<li><a href ="#">Science</a></li>
</ul>
</div><!-- /btn-group -->
<input type = "text" class = "form-control">
</div><!-- /input-group -->
</div><!-- /.col-lg-6 -->
<br>
<div class = "col-lg-6">
<div class = "input-group">
<input type = "text" class = "form-control">
<div class = "input-group-btn">
<button type = "button" class = "btn btn-default" tabindex = "-1">
Course
</button>
<button type = "button" class = "btn btn-default dropdown-toggle"
data-toggle = "dropdown" tabindex = "-1">
<span class = "caret"></span>
<span class = "sr-only">Toggle Dropdown</span>
</button>
<ul class = "dropdown-menu pull-right">
<li><a href = "#">BCA</a></li>
<li><a href = "#">MCA</a></li>
</ul>
</div><!-- /btn-group -->
</div><!-- /input-group -->
</div><!-- /.col-lg-6 -->
</div><!-- /.row -->
</form>
</div>
</body>
</html>