Timer1_tick is not working until postback event

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ASP.NET4

As per topic in discussed. I've assigned one Timer1_Tick (AJAx Control) into my web form user control but it is not working right until i've perform "__doPostBack" in client side and it is not be able to perform automatically once the form is loaded.

Code in markup:

<asp:UpdatePanel ID="TimeSheetUpdate" runat="server" UpdateMode="Conditional">
    <Triggers>
        <asp:AsyncPostBackTrigger ControlID="TimeSheetTimer"  EventName="Tick"/>
    </Triggers>
    <ContentTemplate>
        <asp:Timer ID="TimeSheetTimer" Interval="1000" runat="server" OnTick="TimeSheetTimer_Tick" ClientIDMode="Static"></asp:Timer>
    </ContentTemplate>
</asp:UpdatePanel>

Code Behind:

protected void TimeSheetTimer_Tick(object sender, EventArgs e)
       {
           File.WriteAllText(@"C:\checkTimesheetcontrol.txt", "");
           File.AppendAllText(@"C:\checkTimesheetcontrol.txt", "Check :" + DateTime.Now.Second);
           return;
       }

I need it to be perform ealier once the control in loaded in page.How Can I do for it?

What I have tried:

I've not idea to fixz the problem.