Asp.net file upload control using ajax(update panel)

Today i want to show file upload control using ajax

here is .aspx 

 <asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
    </asp:ToolkitScriptManager>
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
     <Triggers>
        <asp:PostBackTrigger ControlID="Button1"/>
    </Triggers>
  <ContentTemplate>
    <asp:FileUpload ID="FileUpload1" runat="server" />
      <asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" />
    </ContentTemplate>
      </asp:UpdatePanel>

And at .cs page you can get like below.

 protected void Button1_Click(object sender, EventArgs e)
    {
        string a = FileUpload1.PostedFile.FileName;
    }