Bootstrap 3 Skeleton

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">
<br /> <br />     
<div class="container">
    <div class="col-sm-8">
        <div class="input-group">                                            
            <input type="TextBox" ID="datebox" Class="form-control"></input>
            <div class="input-group-btn">
                <button type="button" class="btn btn-primary dropdown-toggle" data-toggle="dropdown">
                    <span class="caret"></span>
                </button>
                <ul id="demolist" class="dropdown-menu">
                    <li><a href="#">A</a></li>
                    <li><a href="#">B</a></li>
                    <li><a href="#">C</a></li>
                </ul>
            </div>
        </div>
    </div>
</div>

CSS

@import url('http://getbootstrap.com/dist/css/bootstrap.css');

JavaScript

$('#demolist li').on('click', function(){
    $('#datebox').val($(this).text());
});