UpdateProgress

<asp:UpdateProgress ID="UpdateProgress1" runat="server">
            <ProgressTemplate>
                <div id="doing" style="z-index: 12000; left: 0px; cursor: wait; position: absolute;
                    top: 0px;">
                    <table>
                        <tr align="center" valign="middle">
                            <td>
                                <table bgcolor="lightgrey" style="filter: Alpha(Opacity=75); 1124px; height: 868px">
                                    <tr align="center" valign="middle">
                                        <td>
                                            <img src="http://images.cnblogs.com/loadingAnimation.gif" />
                                            正在运行....请稍候.
                                        </td>
                                    </tr>
                                </table>
                            </td>
                        </tr>
                    </table>
                </div>
            </ProgressTemplate>
        </asp:UpdateProgress>