[HttpPost]
        public ActionResult ExportExcel(FormCollection form)
        {

            string strHtml = form["hHtml"];
            strHtml = HttpUtility.HtmlDecode(strHtml);//Html解码
            byte[] b = System.Text.Encoding.Default.GetBytes(strHtml);//字串转byte阵列
            return File(b, "application/vnd.ms-excel", "这是Excel.xls");//输出档案给Client端
        }