<asp:UpdatePanel ID="UpdatePanel1" runat="server">
  <ContentTemplate>
        <asp:ScriptManager ID="ScriptManager1" runat="server"> </asp:ScriptManager>
        <asp:Timer ID="Timer1" runat="server" OnTick="Timer1_Tick" Interval="120000">
        </asp:Timer>
        <div class="row">
            <div class="col-lg-4 col-md-4">
                <asp:DropDownList ID="ddlDuration" runat="server" AutoPostBack="true" OnSelectedIndexChanged="ddlDuration_SelectedIndexChanged" CssClass="form-control" Style="margin-left: 5px;">
                    <asp:ListItem Value="1">Today</asp:ListItem>
                    <asp:ListItem Value="3">A week ago</asp:ListItem>
                    <asp:ListItem Value="2">A month ago</asp:ListItem>
                    <asp:ListItem Value="4">A year ago</asp:ListItem>
                </asp:DropDownList>
            </div>
            <div class="col-lg-8 col-md-8">
                <div class="col-lg-1 col-md-1">
                    <label class="control-label">From Date:</label>
                </div>
                <div class="col-lg-3 col-md-3">

                    <asp:TextBox ID="txtDateFrom" runat="server" CssClass="form-control"></asp:TextBox>
                </div>
                <div class="col-lg-1 col-md-1">
                    <label class="control-label">To Date:</label>
                </div>
                <div class="col-lg-3 col-md-3">
                    <asp:TextBox ID="txtDateTo" runat="server" CssClass="form-control"></asp:TextBox>
                </div>
                <asp:Button ID="btnGetReport" runat="server" Text="Apply" CssClass="btn btn-success" Style="background-color: #8B0000; border: #8B0000;" OnClick="btGetReport_Click"></asp:Button>

                <div class="row">
                    <asp:Label ID="dterror" runat="server" />
                </div>
                <hr />
                <div id="chart">
                    <div class="row">
                        <div class="col-md-6">
                            <div class="panel panel-primary">
                                <div class="panel-body">
                                    <div id="ComplaintsByStatus">
                                    </div>
                                </div>
                            </div>
                        </div>
                    </div>
    </ContentTemplate>
</asp:UpdatePanel>

protected void Timer1_Tick(object sender, EventArgs e)
{
    UpdateChart();
}