function refresh_captcha(element) {
    $form = $(element).parents('form');
    var url = location.protocol + "//" + window.location.hostname + ":" + location.port + "/captcha/refresh/";

    $.getJSON(url, {}, function(json) {
        $form.find('input[name="captcha_0"]').val(json.key);
        $form.find('img.captcha').attr('src', json.image_url);
    });

    return false;
}