From 8d7c91b7e499b7dd77b658a1ce5f6c57d302a62a Mon Sep 17 00:00:00 2001
From: smshine <smshine@qq.com>
Date: Sat, 7 Feb 2026 10:47:06 +0800
Subject: [PATCH] fixed a bug

---
 module.js | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/module.js b/module.js
index d672796..2fc66d0 100644
--- a/module.js
+++ b/module.js
@@ -43,9 +43,13 @@ M.mod_programming.init_history = function(Y) {
     dp.sh.HighlightAll('code');
 
     var r = Y.all('.diff1');
-    r.item(0).hide();
+    if (r.size() > 0) {
+        r.item(0).hide();
+    }
     r = Y.all('.diff2');
-    r.item(r.size()-1).hide();
+    if (r.size() > 0) {
+        r.item(r.size() - 1).hide();
+    }
 
     var is_history_diff_form_submitable = function() {
         var f1 = false, f2 = false;