diff --git a/recaptcha.admin.inc b/recaptcha.admin.inc
index bd2dc23..644baa9 100644
--- a/recaptcha.admin.inc
+++ b/recaptcha.admin.inc
@@ -73,6 +73,12 @@ function recaptcha_admin_settings() {
     '#default_value' => variable_get('recaptcha_tabindex', 0),
     '#size' => 4,
   );
+  $form['recaptcha_widget_settings']['recaptcha_data_callback'] = array(
+    '#type' => 'textfield',
+    '#title' => t('Data-callback attribute'),
+    '#description' => t('The name of your callback function to be executed when the user submits a successful CAPTCHA response. The user\'s response, g-recaptcha-response, will be the input for your callback function.'),
+    '#default_value' => variable_get('recaptcha_data_callback', ''),
+  );
   $form['recaptcha_widget_settings']['recaptcha_noscript'] = array(
     '#type' => 'checkbox',
     '#title' => t('Enable fallback for browsers with JavaScript disabled'),
diff --git a/recaptcha.module b/recaptcha.module
index 1e65aab..b32edcc 100644
--- a/recaptcha.module
+++ b/recaptcha.module
@@ -107,6 +107,7 @@ function recaptcha_captcha($op, $captcha_type = '') {
             'data-type' => variable_get('recaptcha_type', 'image'),
             'data-size' => variable_get('recaptcha_size', ''),
             'data-tabindex' => variable_get('recaptcha_tabindex', 0),
+            'data-callback' => variable_get('recaptcha_data_callback', ''),
           );
           // Filter out empty tabindex/size.
           $attributes = array_filter($attributes);