<script type="text/javascript">
    function onClientUploadComplete(sender, e) {debugger
        var ct = e.get_contentType();
        var fn = e.get_fileName();
        var l = e.get_length();
        var p = e.get_path();
        document.getElementById('uploadCompleteInfo').innerHTML = '';
        __doPostBack('upnlNews', '');
    }

    function onClientUploadStart(sender, e) {
        document.getElementById('uploadCompleteInfo').innerHTML = 'Please wait while uploading ' + e._fileName;
    }
</script>

<asp:UpdatePanel runat="server" ID="upnlNews">
    <ContentTemplate>
        <ajaxToolkit:AsyncFileUpload runat="server" ID="fuAttchedDocs"
            ThrobberID="myThrobber"
            UploaderStyle="Traditional"
            OnClientUploadComplete="onClientUploadComplete"
            onuploadedcomplete="fuAttchedDocs_UploadedComplete"
            onuploadedfileerror="fuAttchedDocs_UploadedFileError" />
        <asp:Label runat="server" ID="myThrobber" Style="display: none;">
           <img align="middle" alt="" src="../assets/images/6.gif" />
        </asp:Label>
        <div id="uploadCompleteInfo"></div><br />
    </ContentTemplate>
</asp:UpdatePanel>