Ändrerungen Accordion klappt bei Postback immerr zu

Customers/CustomsAviso.aspx

@@ -269,4 +269,20 @@
             }
         };
     </script>   
+    <script type="text/javascript">
+        $(document).ready(function () {
+            // Get saved data from sessionStorage
+            let selectedCollapse = sessionStorage.getItem('selectedCollapse');
+            if (selectedCollapse != null) {
+                $('accordion-button collapsed').removeClass('show');
+                $(selectedCollapse).addClass('show');
+            }
+            //To set, which one will be opened
+            $('accordion-button collapsed').on('click', function () {
+                let target = $(this).data('target');
+                //Save data to sessionStorage
+                sessionStorage.setItem('selectedCollapse', target);
+            });
+            }
+    </script>
 </asp:Content>