Timer postback twice?

Hi,

I have a timer on my web page as follows:

<asp:Timer ID="Timer1" runat="server" Interval="60000" OnTick="Timer1_Tick">
        </asp:Timer>

But on IE it somehow (strangely) postbacks twice, however it is OK with chrome and FF.

Here is my sample code:

Protected Sub Timer1_Tick(sender As Object, e As EventArgs)

        If panel2.Attributes("class").Contains("hide") Then

            takimadi11.InnerHtml = "Real Madrid" + "<br>" + "5"
            takimadi21.InnerHtml = "Barcelona" + "<br>" + "0"

            Label2.Text = "555"

            panel2.Attributes("class") = "display"
            panel1.Attributes("class") = "hide"
        Else
            takimadi1.InnerHtml = "Fenerbahçe" + "<br>" + "2"
            takimadi2.InnerHtml = "Galatasaray" + "<br>" + "0"



            panel1.Attributes("class") = "display"
            panel2.Attributes("class") = "hide"
        End If


        BindGrid()
    End Sub

How can I fix this issue???

best Regards.