bootstrap-formhelpers不起作用

Question

我无法让bootstrap-formhelpers正常工作。我有bootstrap-formhelpers.js和bootstrap-formhelpers.css文件。有谁看到任何理由？我无法弄清楚

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css">
<link href="css/main.css" rel="stylesheet">
<link href="css/bootstrap-formhelpers.min.css" rel="stylesheet" media="screen">

<div class="modal-body">
    <form role="form">
        <h6>Please submit your information with a description of your interest below. Thank You.</h6>
        <div class="form-group">
            <label for="recipient-name" class="control-label">Name</label>
            <input type="text" class="form-control" id="recipient-name" required>
        </div>
        <div class="form-group">
            <label for="optional-phone" class="control-label">Phone</label>
            <input id="optional-phone" type="text" class="form-control bfh-phone" data-format="+1 (ddd) ddd-dddd">

        </div>
        <div class="form-group">
            <label for="recipient-email" class="control-label">Email</label>
            <input id="recipient-email" type="email" class="form-control" placeholder="Enter Email" required>
        </div>
        <div class="form-group">
            <label for="recipient-message" class="control-label">Message</label>
            <textarea class="form-control" id="recipient-message" required></textarea>
        </div>
    </form>
</div>
<div class="modal-footer">
    <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
    <button id="send_mail" type="button" class="btn btn-primary">Send message</button>
</div>
</div>


<script src="js/jquery-1.11.2.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/js/bootstrap.min.js"></script>
<script src="js/main.js"></script>
<script src="js/bootstrap-formhelpers.js"></script>