解决模态窗口下载问题：弹出与新页面问题修复

模态窗口，解决下载问题
代码如下：
    <base id="goDownload" target="_self" />
    <script type="text/javascript">
        function showMsg()
        {
           var downloadBase=document.getElementById("goDownload");
           var downloadBox=document.getElementById("download");
           download.src=document.URL;
           downloadBase.target="download";
           setTimeout("CancelMsg()",1000);
        }
        function CancelMsg()
        {
           var downloadBase=document.getElementById("goDownload");
           downloadBase.target="_self";
        }
    </script>

    <table width="700px" border="0" cellpadding="0" cellspacing="0" align="center" style=" margin-top:10px;">
        <asp:Repeater ID="RepeaterFileManager" runat="server" OnItemCommand="RepeaterFileManager_OnItemCommand">
            <HeaderTemplate>
                <tr align="center" valign="middle" style="background-color:#A4E3F4;">
                   <td style="width:100px; height:42px;" class="td13">年　　级</td>
                   <td style="width:150px; height:42px;" class="td13">班级名称</td>
                   <td style="width:150px; height:42px;" class="td13">课程名称</td>
                   <td style="width:100px; height:42px;" class="td13">上传教师</td>
                   <td style="width:100px; height:42px;" class="td13">文件类型</td>
                   <td style="width:100px; height:42px;" class="td14">下载</td>
                </tr>