我正在使用plupload进行ajax文件上传。现在plupload.Uploader类有很多选项,但没有一个是附加数据。例如:varuploader=newplupload.Uploader({runtimes:'gears,html5,flash,silverlight,browserplus',browse_button:'pickfiles',container:'contact_container',max_file_size:'10mb',url:'upload.php',flash_swf_url:'/plupload/js/plupload.flash.swf',sil