下载文档时Safari浏览器下载后出现".html"问题

        private static void RenderToBrowser(byte[] bytes, HttpContext context, string downloadname)
        {
            if (context.Request.Browser.Browser == "IE")
            {
                downloadname = HttpUtility.UrlEncode(downloadname, System.Text.Encoding.UTF8).Replace("+", "%20");
            }
            context.Response.ContentType = "application/octet-stream";
            context.Response.AddHeader("Content-Disposition", "attachment;fileName=" + downloadname);
            context.Response.BinaryWrite(bytes);
            context.Response.Flush();
            context.Response.End();
        }