repeater itself is updated, the messagebox was displayed from the c# code, but when the function is called, the original data remains in the array

<script>
             Sys.WebForms.PageRequestManager.getInstance().add_endRequest(mark);
             Sys.WebForms.PageRequestManager.getInstance().beginAsyncPostBack();
             function mark() {
                 var markers3 = [
                     <asp:Repeater ID="rptMarkerss" runat="server" DataSourceID="Search_data">
                         <ItemTemplate>
                         {
                                 "lat": '<%# Eval("lat")%>',
                             "lagg": '<%# Eval("lagg")%>',
                        "url_mark": '<%# Eval("url_mark")%>',
                        "Name_object": '<%# Eval("Имя объекта")%>',
                        "Adress": '<%# Eval("Adress")%>' ,
                        "Number_object": '<%# Eval("Number_object")%>',
                        "Raion":  '<%# Eval("Raion")%>',
                    "District": '<%# Eval("District")%>',
                    "Tip": '<%# Eval("Tip")%>',
                             "Supervisor": '<%# Eval("Supervisor")%>'
                         }
                         </ItemTemplate>
                         <SeparatorTemplate>
                             ,
                         </SeparatorTemplate>
                     </asp:Repeater>
                     <% %>
                 ];
                 alert(markers3.length);
             }
         </script>