Bootstrap 3 - input-group

HTML

<link rel="stylesheet" href="http://getbootstrap.com/dist/css/bootstrap.css">
<script src="http://getbootstrap.com/dist/js/bootstrap.js"></script>
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/font-awesome/4.1.0/css/font-awesome.min.css">
<div class="row">
    <div class="col-xs-6">
        <div class="input-group">
            <input type="text" class="form-control"/>
            <span class="input-group-addon">
                <i class="fa fa-search"></i>
            </span>
        </div>
    </div>
</div>

<div class="row">
    <div class="col-xs-6">
        <div class="input-group">
            <input type="text" class="form-control"/>
            <button class="input-group-addon" type="submit">
                <i class="fa fa-search"></i>
            </button>
        </div>
    </div>
</div>