<form>
<input type="file" name="txt_file" id="txt_file" multiple class="file-loading" />
</form>

$('#txt_file').fileinput('upload');

function initFileInput(ctrlName, uploadUrl) {
  var control = $('#' + ctrlName);
  control.fileinput({
   language: 'zh', //设置语言
   uploadUrl: uploadUrl, //上传的地址
   allowedFileExtensions : ['txt', 'doc','docx'],//接收的文件后缀
   showUpload: false, //是否显示上传按钮
   showCaption: false,//是否显示标题
   enctype: 'multipart/form-data',
   browseClass: "btn btn-primary", //按钮样式    
   previewFileIcon: "<i class='glyphicon glyphicon-king'></i>",
   uploadExtraData: function() { //额外参数的关键点
     return data;
    }
   }).on("fileuploaded", function (event, data, previewId, index) {
    fileResponseData.push(data.response.Attach);
   });
 }
 
 //-----入口方法-----
 $(function() {
  initFileInput("txt_file", "/updateFile.do");
 });