form_file.js

$('form').submit(function(){
    event.preventDefault();
    var fd = new FormData($('.employee-file-form')[0]);
    var btn = $(this).find('.js-upload-field-employee');
    btn.button('loading');
    $.ajax({
        url: '/api/v3/upload_field_employees/',
        type: 'POST',
        data: fd,
        cache: false,
        contentType: false,
        processData: false,
        success: function(response){console.log(reponse);},
    }).always(function() {
        btn.button('reset');
    });
})