The following code shows how to create dropdown with envelope icon.
<!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/2.2.2/js/bootstrap.min.js"></script>
<script type='text/javascript'>
$(window).load(function(){<!--from w w w . j a va2s . c o m-->
$('.dropdown-toggle').dropdown();
$('#divNewNotifications li > a').click(function(){
$('#text').text($(this).html());
});
});
</script>
</head>
<body>
<ul class="nav nav-pills left">
<li class="dropdown active span8"><a class="dropdown-toggle"
id="inp_impact" data-toggle="dropdown">
<i class="icon icon-envelope icon-white"></i>
<span id="text">Select</span>
<span class="caret"></span></a>
<ul ID="divNewNotifications" class="dropdown-menu">
<li><a>One</a></li>
<li><a>Two</a></li>
<li><a>Three</a></li>
</ul>
</li>
</ul>
</body>
</html>