For instances where you have too many items in your navbar to
fight within the viewport of a small device, add .nav-collapse-scrollable
to your navbar's .nav-collapse to set a max-height and smooth scrolling.
<!DOCTYPE HTML>
<html>
<head>
<link href="http://java2s.com/style/bootstrap.min.css" rel="stylesheet">
<script src="http://java2s.com/style/jquery-1.8.0.min.js"></script>
<script src="http://java2s.com/style/bootstrap.min.js"></script>
</head><!-- w ww .j a v a 2 s . c o m-->
<body style='margin: 20px;'>
<div class="navbar">
<div class="container">
<button type="button" class="navbar-toggle" data-toggle="collapse"
data-target=".bs-navbar-scroll-collapse">
<span class="icon-bar"></span> <span class="icon-bar"></span> <span
class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#">Title</a>
<div
class="collapse nav-collapse nav-collapse-scrollable bs-navbar-scroll-collapse">
<ul class="nav navbar-nav">
<li class="active"><a href="#">Home</a></li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
<li><a href="#">Link</a></li>
</ul>
<form class="navbar-form pull-left" action="">
<input type="text" class="form-control col-lg-8"
placeholder="Search">
</form>
</div>
<!-- /.nav-collapse -->
</div>
<!-- /.container -->
</div>
</body>
</html>