<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<!------ Include the above in your HEAD tag ---------->
<form class="form-horizontal">
<fieldset>
<!-- Form Name -->
<legend>Main</legend>
<!-- Button -->
<div class="form-group">
<button id="singlebutton" name="singlebutton" class="btn btn-primary">Button</button>
</div>
</fieldset>
</form>
