跨域bug修复1

frontend/admin/conduct.php

@@ -56,7 +56,7 @@ include __DIR__ . '/../includes/header.php';
 </div>
 
 <script>
-let selectedStudentIds = [];
+var selectedStudentIds = [];
 
 async function loadStudents() {
     const res = await apiGet('/api/admin/students');

frontend/admin/homework.php

@@ -91,7 +91,7 @@ include __DIR__ . '/../includes/header.php';
 </div>
 
 <script>
-let selectedStudentIds = [];
+var selectedStudentIds = [];
 
 // 初始化扣分配置
 const hwMaxPoints = window.HOMEWORK_MAX_POINTS || 3;