diff --git a/pollanon.module b/pollanon.module
index 5eca626..82ec344 100644
--- a/pollanon.module
+++ b/pollanon.module
@@ -42,10 +42,10 @@ function pollanon_form_alter(&$form, &$form_state, $form_id) {
     $node = $form['#node'];
 
     if (empty($form['#attributes']['class'])) {
-      $form['#attributes']['class'] = 'pollanon';
+      $form['#attributes']['class'] = array('pollanon');
     }
     else {
-      $form['#attributes']['class'] .= ' pollanon';
+      $form['#attributes']['class'][] = 'pollanon';
     }
 
     $results = _pollanon_poll_results($node->nid);