function enqueue_mp3_scripts_init($form, $is_ajax) {
         if ( $is_ajax ) {
        wp_enqueue_script( 'mp3-script', plugin_dir_url(__FILE__) . 'js/scripts.js', array('jquery'), 1.0 ); // jQuery will be included automatically
        wp_localize_script( 'mp3-script', 'mp3_object', array( 'ajaxurl' => admin_url( 'admin-ajax.php' ) ) ); // setting ajaxurl
         }
        }

add_action('gform_enqueue_scripts', 'enqueue_mp3_scripts_init', 10, 2);

function ajax_mp3_func() {

    if( isset($_POST['files']) )  {
        echo $_POST['files'];
        }

    die(); // stop executing script
}

add_action( 'wp_ajax_ajax_mp3', 'ajax_mp3_func' ); // ajax for logged in users
add_action( 'wp_ajax_nopriv_ajax_mp3', 'ajax_mp3_func' ); // ajax for not logged in users