diff --git uc_dependent_attributes.module uc_dependent_attributes.module
index 7124453..1ef0ba8 100644
--- uc_dependent_attributes.module
+++ uc_dependent_attributes.module
@@ -47,7 +47,7 @@ function uc_dependent_attributes_form_alter(&$form, $form_state, $form_id) {
   // Filter attribute/option conbinations on the product add_to_cart form if
   // submitted via ajaxSubmit
 
-  if (strstr($form_id, 'uc_product_add_to_cart_form_') && !empty($_POST)) {
+  if (substr($form_id, 'uc_product_add_to_cart_form') && !empty($_POST)) {
     // Only attempt to adjust attributes if they exist
     if (isset($form['attributes'])) {
       // Build a 2-dimensional array of possible attribute and option ids