From 7f50a2cbd953adad0c4b85d793b8a4a36af2b79a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=AD=99=E5=B9=BF=E6=98=8E?= <sunguangming@cnezsoft.com>
Date: Wed, 16 Feb 2022 11:26:40 +0800
Subject: [PATCH] * Fix code error.

---
 lib/base/front/front.class.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/base/front/front.class.php b/lib/base/front/front.class.php
index d6993697fa..bb6db7f452 100644
--- a/lib/base/front/front.class.php
+++ b/lib/base/front/front.class.php
@@ -488,7 +488,7 @@ class baseHTML
         if(empty($label)) $label = $lang->goback;
 
         $gobackLink   = "<a href='javascript:history.go(-1)' class='btn btn-back $class' $misc>{$label}</a>";
-        $tab          = $_COOKIE['tab'];
+        $tab          = isset($_COOKIE['tab']) ? $_COOKIE['tab'] : '';
         $referer      = isset($_SERVER['HTTP_REFERER']) ? $_SERVER['HTTP_REFERER'] : '';
         $refererParts = parse_url($referer);