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>

Customers/CustomsAviso.aspx.vb

@@ -53,7 +53,6 @@ Partial Class Kundenbereich_Default
         Dim darkblue = Drawing.Color.FromArgb(4, 51, 129)
 
         tr.BackColor = white
-
         If t1.Text = "" Then
             t1.BackColor = white
             t1.ForeColor = schwarz
@@ -433,7 +432,7 @@ Partial Class Kundenbereich_Default
         If pickdate1.Text = "" Then
             pickdate1.BorderColor = Drawing.Color.Red
         Else
-            pickdate1.BorderStyle = 1
+            pickdate1.BorderStyle = BorderStyle.None
         End If
     End Sub
 
@@ -442,7 +441,7 @@ Partial Class Kundenbereich_Default
         If pickdate2.Text = "" Then
             pickdate2.Attributes.Add("Border", "2px solid red")
         Else
-            pickdate2.Attributes.Add("Border", "None")
+            pickdate2.BorderStyle = BorderStyle.None
         End If
     End Sub