diff --git a/Zhihu-Enhanced.user.js b/Zhihu-Enhanced.user.js
index 6538750..b5a00c2 100644
--- a/Zhihu-Enhanced.user.js
+++ b/Zhihu-Enhanced.user.js
@@ -7,6 +7,7 @@
 // @match        *://zhuanlan.zhihu.com/*
 // @icon         https://static.zhihu.com/heifetz/favicon.ico
 // @require      https://cdn.bootcss.com/jquery/3.4.1/jquery.min.js
+/* globals $ */
 // @grant        GM_registerMenuCommand
 // @grant        GM_unregisterMenuCommand
 // @grant        GM_openInTab