hi

Ican solve this problem  with this code:

in code behinde:

Public s As String    Public Sub RaiseCallbackEvent(ByVal eventArgument As String) Implements System.Web.UI.ICallbackEventHandler.RaiseCallbackEvent
            s = eventArgument
            Context.Session("n") = eventArgument
        End Sub
        Public Function GetCallbackResult() As String Implements System.Web.UI.ICallbackEventHandler.GetCallbackResult
            Return s
        End Function

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
            Try

               Dim cm As ClientScriptManager = Page.ClientScript
                sCallBackFunctionInvocation = cm.GetCallbackEventReference(Me, "message", "ShowServerTime", "context", "OnError", True)
                createtabdynamic()

                If Not Session("n") Is Nothing Then

                    If Not TabContainer1.Tabs.FindTab(Session("n").ToString) Is Nothing Then
                        TabContainer1.SelectedIndex = Integer.Parse(Session("n").ToString.Remove(0, 2)) - 1
                        txtbox.Text = Session("n").ToString.Remove(0, 2)
                        ''txtbox.Text = Session("n").ToString

                    End If
                     End If
End sub

and in ascx file:

<script language="javascript">
 

         function GetServerTime(evt,element)
         {
            var message =dnn.dom.getAttr(element, 'tid');
            var context = '';
           
            <%=sCallBackFunctionInvocation%>
         }
        
         function ShowServerTime(timeMessage, context) {
            var p='';
            // + message);
         }

      </script>