JSFiddle - React, Tailwind, and code Playground

by A B

HTML

<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.1/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.1/css/bootstrap.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.6.3/js/bootstrap-select.js"></script>
<link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.6.3/css/bootstrap-select.css">
<select class="selectpicker" data-style="btn-primary btn-sm">
    <option>Mustard</option>
    <option>Ketchup</option>
    <option>Relish</option>
</select>

<br />

<button type="button" id="add-form-control">Add form-controll</button>

<button type="button" id="remove-form-control">Remove form-controll</button>

JavaScript

$('#add-form-control').on('click', function(){
    $('.selectpicker').addClass('form-control');
});

$('#remove-form-control').on('click', function(){
    $('.selectpicker').removeClass('form-control');
});