The following code shows how to show modal dialog via Javascript.
<!DOCTYPE html>
<html lang="en">
<head>
<link rel="stylesheet"
href="http://netdna.bootstrapcdn.com/bootstrap/3.0.3/css/bootstrap.min.css">
<link rel="stylesheet"
href="http://netdna.bootstrapcdn.com/bootstrap/3.0.3/css/bootstrap-theme.min.css">
<script type="text/javascript"
src="http://code.jquery.com/jquery.min.js"></script>
<script
src="http://netdna.bootstrapcdn.com/bootstrap/3.0.3/js/bootstrap.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){<!--from w w w . j a v a 2s .c o m-->
$("#myModal").modal('show');
});
</script>
</head>
<body>
<div id="myModal" class="modal fade">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal"
aria-hidden="true">×</button>
<h4 class="modal-title">Confirmation</h4>
</div>
<div class="modal-body">
<p>Do you want to save changes you made to document before
closing?</p>
<p class="text-warning">
<small>If you don't save, your changes will be lost.</small>
</p>
</div>
<div class="modal-footer">
<button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
<button type="button" class="btn btn-primary">Save changes</button>
</div>
</div>
</div>
</div>
</body>
</html>