The following code shows how to create dropdown with caret.
<!DOCTYPE html>
<html>
<head>
<script type='text/javascript'
src='https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js'></script>
<link rel="stylesheet" type="text/css"
href="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.2.2/css/bootstrap-combined.min.css">
<script type='text/javascript'
src="http://netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/js/bootstrap.min.js"></script>
<style type='text/css'>
#idValue {<!-- w w w. j a va 2 s . co m-->
width: 40px;
height: 20px;
background-color: #E6E6E6;
}
</style>
</head>
<body style='margin:30px'>
<br />
<br />
<div class="dropdown btn-group">
<a class="btn dropdown-toggle" data-toggle="dropdown" href="#">
Select <span class="caret"></span>
</a>
<ul id="selectId" class="dropdown-menu">
<li value="10"><a href="#">10</a></li>
<li value="20"><a href="#">20</a></li>
<li value="30"><a href="#">30</a></li>
<li value="40"><a href="#">40</a></li>
<li value="50"><a href="#">50</a></li>
<li value="60"><a href="#">60</a></li>
<li value="70"><a href="#">70</a></li>
</ul>
</div>
</body>
</html>