<style type="text/css">
    .fileLink{position: relative;display: inline-block;background: #fff;border: 1px solid #0980D0;border-radius: 4px;padding: 2px 8px;margin-left:10px;margin-top:10px;overflow: hidden;color: #1E88C7;text-decoration: none;text-indent: 0;line-height: 20px;}
    .fileLink input {position: absolute;font-size: 100px;right: 0;top: 0;opacity: 0;}
    .fileLink:hover {background: #AADFFD;border-color: #78C3F3;cursor:pointer;color: #004974;text-decoration: none;}
  </style>
<span class="fL fileLink" style="padding-left: 10px;">选择文件<input type="file" id="uploadify" name="uploadify" value="上传数据" /></span>
<script src="../../Plugins/jquery/jquery-1.7.2.min.js" type="text/javascript"></script>
<script src="../../Plugins/ajaxfileupload.js" type="text/javascript"></script>
<script>
    $("#uploadify").on("change", function () {
      //var file = $("#uploadify")[0].files[0];
      $.ajaxFileUpload({
        url: './ImportDynamic.ashx',
        fileElementId: 'uploadify',
        dataType: 'text',
        success: function (data, status) {
          alert(1);
        },
        error: function () { }
      });
    });
</script>
一般处理程序：
      context.Response.ContentType = "text/plain";
      var filePath = "uploadfile/xxx.xls";
      filePath = context.Server.MapPath(filePath);
      Import.GetCommonReportFile(filePath);
      //context.Response.Write("返回文本数据，否则前台就会报如上错误");