I tried the following code but it is not working
<script type="text/javascript">
$(document).ready(function() {
$('#myModal').modal('show');
});
</script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.0.0/jquery.min.js"></script>
<div id="myModal" class="modal fade bs-example-modal-sm" tabindex="-1" role="dialog" aria-labelledby="mySmallModalLabel" aria-hidden="true">
<div class="modal-dialog modal-sm">
<div class="modal-content">
Conteudo
</div>
</div>
</div>