what is invoice

@@ -707,6 +707,7 @@ class CartModel
                 ksort($result['piaoTypes']);
                 $result['piaoTypes'] = array_values($result['piaoTypes']);
                 $result['receiverMobile'] = isset($userInfo['data']['mobile']) && $userInfo['data']['mobile'] ? $userInfo['data']['mobile'] : '';
+                $result['invoiceUrl'] = 'http://www.yohobuy.com/help?category_id=99';
             }
 
             /* 需购买的商品 */