StackOverflow - Bootstrap Modal Messages Update Badge Count
http://stackoverflow.com/questions/31927799/bootstrap-modal-and-badges/31927970#31927970
HTML
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<p data-toggle="modal" data-target="#messagesModal"><a href="#">Messages <span class="badge"></span></a></p>
<!-- Modal -->
<div class="modal fade" id="messagesModal" role="dialog">
<div class="modal-dialog">
<!-- Modal content-->
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal">4</button>
<h4 class="modal-title">Messages</h4>
</div>
<div class="modal-body">
<div class="alert fade in"> <a href="#" class="close" data-dismiss="alert" aria-label="close">×</a>
<strong>Message 01</strong>:
<p>Lipsum Ipsum</p>
</div>
<div class="alert fade in"> <a href="#" class="close" data-dismiss="alert" aria-label="close">×</a>
<strong>Message 02</strong>:
<p>Ipsum Lipsum</p>
</div>
<div class="alert fade in"> <a href="#" class="close" data-dismiss="alert" aria-label="close">×</a>
<strong>Message 03</strong>:
<p>Lipsum Ipsum</p>
</div>
</div>
<div class="modal-footer">
<div class="col-md-8 pull-left"></div>
<div class="col-md-4">
<button type="button" class="btn btn-default pull-right" data-dismiss="modal">Close</button>
</div>
</div>
</div>
</div>
</div>
JavaScript
$(document).ready(function() {
$(".badge").text($(".alert").length);
$('#messagesModal').on('hidden.bs.modal', function() {
$(".badge").text($(".alert").length);
if ($(".alert").length == 0) {
$(".badge").text("No messages");
}
});
});