The following code shows how to slide down/up dropdown.
<!DOCTYPE html>
<html>
<head>
<script type='text/javascript'
src='http://code.jquery.com/jquery-1.10.1.js'></script>
<link rel="stylesheet" type="text/css"
href="http://netdna.bootstrapcdn.com/bootstrap/3.0.2/css/bootstrap.min.css">
<script type='text/javascript'
src="http://netdna.bootstrapcdn.com/bootstrap/3.0.2/js/bootstrap.min.js"></script>
<script type='text/javascript'>
$(window).load(function(){<!--from www. ja v a 2s .co m-->
$(document).ready(function(){
$('.dropdown').on('show.bs.dropdown', function(e){
$(this).find('.dropdown-menu').first().stop(true, true).slideDown();
});
$('.dropdown').on('hide.bs.dropdown', function(e){
$(this).find('.dropdown-menu').first().stop(true, true).slideUp();
});
});
});
</script>
</head>
<body>
<div id="netsec_menu" class="row" style="width: 100%;">
<div class="navbar netsec_navbar">
<div class="container">
<nav class="navbar-default netsec_navbar-default" role="navigation">
<!-- Toggle button for mobile display -->
<div class="navbar-header">
<button type="button" class="navbar-toggle netsec_navbar-toggle"
data-toggle="collapse" data-target="#netsec_mainmenu">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
</div>
<!-- Menu Content -->
<div class="collapse navbar-collapse" id="netsec_mainmenu">
<ul class="nav navbar-nav netsec_menucontent">
<li class="dropdown"><a href="#" class="dropdown-toggle"
data-toggle="dropdown">DropDown Menu <b class="caret"></b></a>
<ul class="dropdown-menu">
<li><a href="#">Sub-Item 1</a></li>
<li><a href="#">Sub-Item 2</a></li>
<li><a href="#">Sub-Item 3</a></li>
<li><a href="#">Sub-Item 4</a></li>
<li><a href="#">Sub-Item 5</a></li>
<li><a href="#">Sub-Item 6</a></li>
</ul></li>
<li><a href="#">Nav Item</a></li>
<li><a href="#">Nav Item</a></li>
<li><a href="#">Nav Item</a></li>
<li><a href="#">Nav Item</a></li>
<li><a href="#">Nav Item</a></li>
</ul>
</div>
</nav>
</div>
</div>
</div>
</body>
</html>