I'm working on a contact form for a website and I've run into a problem. I need to add a field to the form containing a phone number. I've added the field into the HTML and into the PHP script, and it sends the "Phone Number:" but not the actual value. 

HTML

```html
<form action="php/contact-form.php" id="contactForm" type="post">
    <div class="row">
  <div class="form-group">
       <div class="col-md-6">
           <label>Uw naam</label>
    <input type="text" value="" data-msg-required="Vul alstublieft uw naam in." maxlength="100" class="form-control" name="name" id="name">
       </div>
       <div class="col-md-6">
     <label>Uw emailadres</label>
     <input type="email" value="" data-msg-required="Vul alstublieft uw emailadres in." data-msg-email="Voer alstublieft een correct emailadres in." maxlength="100" class="form-control" name="email" id="email">
       </div>
   </div>
    </div>
 <div class="row">
      <div class="form-group">
          <div class="col-md-6">
               <label>Uw telefoonnummer</label>
                      <input type="text" value="" data-msg-required="Vul alstublieft uw telefoonnummer in." maxlength="100" class="form-control" name="phone" id="phone">
   </div>
          <div class="col-md-6">
              <label>Onderwerp</label>
       <input type="text" value="" data-msg-required="Vul alstublieft een onderwerp in." maxlength="100" class="form-control" name="subject" id="subject">
  </div>
  </div>
     </div>
     <div class="row">
  <div class="form-group">
       <div class="col-md-12">
     <label>Uw bericht</label>
     <textarea maxlength="5000" data-msg-required="Vul alstublieft uw bericht in." rows="10" class="form-control" name="message" id="message"></textarea>
             </div>
  </div>
     </div>
     <div class="row">
   <div class="col-md-12">
     <input type="submit" value="Verstuur" class="btn btn-primary btn-lg" data-loading-text="Laden...">
   </div>
  </div>
</form>
```

PHP

```html
<?php
session_cache_limiter('nocache');
header('Expires: ' . gmdate('r', 0));

header('Content-type: application/json');

// Enter your email address below.
$to = 'email@removedforprivacyreasons.com';

$subject = $_POST['subject'];

if($to) {
 $name = $_POST['name'];
 $email = $_POST['email'];

 $fields = array(
  0 => array(
   'text' => 'Naam',
   'val' => $_POST['name']
  ),
  1 => array(
   'text' => 'Emailadres',
   'val' => $_POST['email']
  ),
  2 => array(
   'text' => 'Telefoonnummer',
   'val' => $_POST['phone']
  ),
  3 => array(
   'text' => 'Bericht',
   'val' => $_POST['message']
  )
 );

 $message = "";

 foreach($fields as $field) {
  $message .= $field['text'].": " . htmlspecialchars($field['val'], ENT_QUOTES) . "<br>\n";
 }

 $headers = '';
 $headers .= 'From: ' . $name . ' <' . $email . '>' . "\r\n";
 $headers .= "Reply-To: " .  $email . "\r\n";
 $headers .= "MIME-Version: 1.0\r\n";
 $headers .= "Content-Type: text/html; charset=UTF-8\r\n";

 if (mail($to, $subject, $message, $headers)){
  $arrResult = array ('response'=>'success');
 } else{
  $arrResult = array ('response'=>'error');
 }

 echo json_encode($arrResult);

} else {

 $arrResult = array ('response'=>'error');
 echo json_encode($arrResult);

}
?>
```

What have I overlooked?