<link href="//netdna.bootstrapcdn.com/bootstrap/3.0.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.1/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<div class="container">
<div class="row">
<h2>Bootstrap 3 .input-xs, since it doesn't exists.</h2>
</div>
<P>Sample usage in input-group</P>
<div class="input-group">
<span class="input-group-btn">
<button class="btn btn-xs btn-success">
<i class="glyphicon glyphicon-plus"></i>
</button>
</span>
<input type="text" class="form-control input-xs" />
<span class="input-group-btn">
<button class="btn btn-xs btn-danger">
<i class="glyphicon glyphicon-minus"></i>
</button>
</span>
</div>
<p>Alternatively:</p>
<div class="input-group input-group-xs">
<span class="input-group-btn">
<button class="btn btn-success">
<i class="glyphicon glyphicon-plus"></i>
</button>
</span>
<input type="text" class="form-control" />
<span class="input-group-btn">
<button class="btn btn-danger">
<i class="glyphicon glyphicon-minus"></i>