问从后面的VB代码调用javascript代码时遇到麻烦

EN

<asp:HiddenField  runat="server" id ="confirm_value"/>

If -1000 < RadNumericTextBox1.Text Then
        If confirm_value.Value <> "Yes" Then
            Dim cs As ClientScriptManager = Page.ClientScript
            ' Check to see if the startup script is already registered.
            If (Not cs.IsStartupScriptRegistered(Me.GetType(), "ConfirmScriptRXOrder")) Then
                Dim cstext1 As String = "Confirm('This item has less in stock than your order. Do you want to order it anyway?');"
                'Dim cstext1 As String = "alert('Hi there!');"
                cs.RegisterStartupScript(Me.GetType(), "ConfirmScriptRXOrder", cstext1, True)
            End If
            'return here, JS will re-click submit button after okaying the message,.
            Return
        Else
            confirm_value.Value = "No"
            Mycart(ddCyl.SelectedValue.ToString, ddSph.SelectedItem.Text, ddCyl.SelectedItem.Text, RadNumericTextBox1.Text, tbtray.Text)

            RadGrid1.DataBind()
        End If
    End If

<script type = "text/javascript">
    function Confirm(message) {
        if (confirm(message)) {
            var x = document.getElementById('<%= confirm_value.ClientID%>');
            x.value = 'Yes';
            document.getElementById('<%=btnOrder.ClientID%>').click();
        } else {
            var x = document.getElementById('<%= confirm_value.ClientID%>');
            x.value = 'No';
        }
    }
</script>