diff --git a/src/CaptchaController.php b/src/CaptchaController.php
index 37fa592..f852b5a 100644
--- a/src/CaptchaController.php
+++ b/src/CaptchaController.php
@@ -12,9 +12,8 @@
 namespace think\captcha;
 
 use think\Config;
-use think\Controller;
 
-class CaptchaController extends Controller
+class CaptchaController
 {
     public function index($id = "")
     {
diff --git a/src/helper.php b/src/helper.php
index dd0b407..555077c 100644
--- a/src/helper.php
+++ b/src/helper.php
@@ -35,7 +35,7 @@ function captcha($id = "", $config = [])
  */
 function captcha_src($id = "")
 {
-    return \think\Url::build('/captcha' . $id ? "/{$id}" : '');
+    return \think\Url::build('/captcha' . ($id ? "/{$id}" : ''));
 }