AsyncFileUpload control doesnt work

I am just trying to simple file upload using `AsyncFileUpload` .I am not getting any error but nothing happens when i choose a file .I dont undersand whats wrong Everything look fine to me .Could you please help. This is what i have so far                   protected void AsyncFileUpload1_UploadedComplete(object sender,             AsyncFileUploadEventArgs e)            {         string filename = System.IO.Path.GetFileName(AsyncFileUpload1.FileName);         AsyncFileUpload1.SaveAs(Server.MapPath("Files/") + filename);         }             <form id="form1" runat="server&qu ...