example add extra data in Jquery File Upload - https://blueimp.github.io/jQuery-File-Upload/‎

gistfile1.js

    $("#fileupload").fileupload({       
        dataType: 'json',
        url:'/kelas/{{ kelas.id }}/new/image/',
        add: function (e, data) {
            no_img = 1
            $("#btnSubmit").click(function () {
                title = $("input#titleimg").val();
                data.formData = {title:title, no_img:no_img};
                data.submit();
                no_img += 1
            });
        },
        done: function (e, data) {
            $('#progress .bar').css('width', '0%');
            location = url;
         },
        progressall: function (e, data) {
            var progress = parseInt(data.loaded / data.total * 100, 10);
            $('#progress .bar').css({'width':progress + '%', 'float':'left'});
        }
    });