Получает имя файла при отсылке через форму

form.html

<!-- Contact form -->
<form id="contact-form" class="contact-form" name="" method="POST" action="http://site.ee/ru/message-sent.htm" enctype="multipart/form-data">
    <input type="hidden" name="MAX_FILE_SIZE" value="2000000" />
    <legend>Me koostame hinnapakkumise ja saadame selle Teile juba ühe tunni jooksul!</legend>
    <div class="input-field">
        <input type="text" placeholder="Nimi:" value="" name="name" required>
    </div>
    <div class="input-field">
        <input type="text" placeholder="Telefon:" value="" name="phone" required>
    </div>
    <div class="input-field">
        <input type="email" placeholder="E-mail" value="" name="email">
    </div>
    <div class="input-upload">
        <input type="file" name="attachment" value="" />Lisa fail</div>
<span id="attachment"></span>

    <div class="input-field">
        <textarea placeholder="Kirjuta tekst siia" id="message" rows="15" name="message"></textarea>
    </div>
    <button type="submit" id="submit" name="submit">Saada päring</button>
</form>
<!-- Contact form -->

script.js

$('input[type="file"]').on('change', function (event, files, label) {
    var file_name = this.value.replace(/\\/g, '/').replace(/.*\//, '');
    $('#attachment').text(file_name);
});

$( "button" ).click(function() {
  $( "#contact-form" ).submit();
});