How to display comments length

I used this:

function wpb_countx() {
    wp_enqueue_script('jquery');
    ?>
        <script>
   jQuery(function($) {
    // configure
    var comment_input = $( '#commentform textarea' );
    var submit_button = $( '#commentform .form-submit' );
    var comment_limit_chars = 1400;
    // stop editing here

    // display how many characters are left
    $( '<div class="comment_limit_info"><span>' + comment_limit_chars + '</span> zbývá znaků</div>' ).insertAfter( comment_input );

    comment_input.bind( 'keyup', function() {
        // calculate characters left
        var comment_length = $(this).val().length;
        var chars_left = comment_limit_chars - comment_length;

        // display characters left
        $( '.comment_limit_info span' ).html( chars_left );

        // hide submit button if too many chars were used
        if (submit_button)
            ( chars_left < 0 ) ? submit_button.hide() : submit_button.show();
    });
}); 
        </script>
    <?php
}
add_action('wp_footer', 'wpb_countx');