Index: recaptcha/js/recaptcha.invisible.js
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- recaptcha/js/recaptcha.invisible.js	(date 1489595402000)
+++ recaptcha/js/recaptcha.invisible.js	(revision )
@@ -1,1 +1,58 @@
+/**
+ * @file
+ * Invisible reCaptcha behaviors.
+ */
+
+/**
+ * ID of the form.
+ *
+ * @type {string}
+ */
+
+var submittedFormId = '';
+/**
+ * reCaptcha data-callback that submits the form.
+ *
+ * @param token
+ *   The validation token.
+ */
+function onInvisibleSubmit(token) {
+  document.getElementById(submittedFormId).submit();
+}
+
+(function ($) {
+  /**
+   * Handles the submission of the form with the invisible reCaptcha.
+   *
+   * @type {Drupal~behavior}
+   *
+   * @prop {Drupal~behaviorAttach} attach
+   *   Attaches the behavior for the invisible reCaptcha.
+   */
+
+  Drupal.behaviors.invisibleRecaptcha = {
+    attach: function(context, settings) {
+      $('form', context).each(function () {
+        var $form = $(this);
+
+        if ($form.find('.g-recaptcha[data-size="invisible"]').length) {
+          $form.find('input[type="submit"]').click(function (e) {
+            e.preventDefault();
+            validateInvisibleCaptcha($form);
+          });
+        }
+      });
+
+      /**
+       * Triggers the reCaptcha to validate the form.
+       *
+       * @param {jQuery} $form
+       *   The form object to be validated.
+       */
+      function validateInvisibleCaptcha($form) {
+        submittedFormId = $form.attr('id');
+        grecaptcha.execute();
+      }
+    }
+  };
+})(jQuery);
 
\ No newline at end of file
Index: recaptcha/recaptcha.admin.inc
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- recaptcha/recaptcha.admin.inc	(date 1489595402000)
+++ recaptcha/recaptcha.admin.inc	(revision )
@@ -62,9 +62,26 @@
     '#options' => array(
       '' => t('Normal (default)'),
       'compact' => t('Compact'),
+      'invisible' => t('Invisible'),
     ),
     '#title' => t('Size'),
     '#type' => 'select',
+  );
+  $form['recaptcha_widget_settings']['recaptcha_badge'] = array(
+    '#default_value' => variable_get('recaptcha_badge', 'bottomright'),
+    '#description' => t('Reposition the reCAPTCHA badge. "Inline" allows you to control the CSS.'),
+    '#options' => array(
+      'bottomright' => t('Bottom Right (default)'),
+      'bottomleft' => t('Bottom Left'),
+      'inline' => t('Inline'),
+    ),
+    '#title' => t('Badge'),
+    '#type' => 'select',
+    '#states' => array(
+      'visible' => array(
+        ':input[name="recaptcha_size"]' => array('value' => 'invisible'),
+      ),
+    ),
   );
   $form['recaptcha_widget_settings']['recaptcha_tabindex'] = array(
     '#type' => 'textfield',
Index: recaptcha/recaptcha.module
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- recaptcha/recaptcha.module	(date 1489595402000)
+++ recaptcha/recaptcha.module	(revision )
@@ -108,6 +108,16 @@
             'data-size' => variable_get('recaptcha_size', ''),
             'data-tabindex' => variable_get('recaptcha_tabindex', 0),
           );
+
+          if (variable_get('recaptcha_size', '') == 'invisible') {
+            $attributes['data-callback'] = 'onInvisibleSubmit';
+            $attributes['data-badge'] = variable_get('recaptcha_badge', 'bottomright');
+
+            $captcha['form']['#attached']['js'] = array(
+              drupal_get_path('module', 'recaptcha') . '/js/recaptcha.invisible.js',
+            );
+          }
+
           // Filter out empty tabindex/size.
           $attributes = array_filter($attributes);