blueimp-jQuery-File-Upload如何设置超过一定的文件数就弹出提示框

blueimp-jQuery-File-Upload如何设置超过一定的文件数就弹出框，我设置的不行呢，即使设置maxNumberOfFiles也不起作用

https://github.com/blueimp/jQ...

$(function() {
    $.getScript('{{ MEDIA_URL }}js/jquery.fileupload.min.js', function () {
        
        var popup = $('#upload-file-dialog2').addClass('fixed-upload-file-dialog');;
        var popup_height = '200px';
        popup.css({'height': popup_height}).data('height', popup_height);

        var fu_status = $('.status', popup),
            total_progress = $('.total-progress', popup),
            cancel_all_btn = $('.fileupload-buttonbar .cancel', popup),
            close_icon = $('.close', popup),
            saving_tip = $('.saving-tip', popup);

        var fu_status_ = {
            'uploading': "{% trans "File Uploading..." %}",
            'complete': "{% trans "File Upload complete" %}",
            'canceled': "{% trans "File Upload canceled" %}",
            'failed': "{% trans "File Upload failed" %}"
        };
        
        popup.fileupload({
            fileInput: $('#upload-file2 input'),
            paramName: 'file',
            // customize it for 'done'
            getFilesFromResponse: function (data) {
                if (data.result) {
                    return data.result;
                }
            },
            autoUpload:true,
            {% if max_upload_file_size %}
            maxFileSize: {{ max_upload_file_size }}, // in bytes
            {% endif %}
            maxNumberOfFiles: 500,
            sequentialUploads: true
        })
        .bind('fileuploadadd', function(e, data) {
            var files = e.target.files; // FileList
            console.log(files[0].length);
            popup.removeClass('hide');
            cancel_all_btn.removeClass('hide');
            close_icon.addClass('hide');
        })
        .bind('fileuploadstart', function() {
            fu_status.html(fu_status_.uploading);
        })
        .bind('fileuploadsubmit', function(e, data) {
            if (data.files.length == 0) {
                return false;
            }
            var file = data.files[0];
            var uu = data.files[0].webkitRelativePath;

            if (!file.error) {
                $.ajax({
                    url: '{% url 'get_file_op_url' repo.id %}',
                    cache: false,
                    data: {
                        'op_type': 'upload',
                        'path': cur_path,
                        'dir-structure':uu,
                    },
                    dataType: 'json',
                    success: function(ret) {
                        data.url = ret['url'];
                        data.formData = {parent_dir:cur_path+ret['path']}
                        
                        data.jqXHR = popup.fileupload('send', data);
                    },
                    error: function() {
                        file.error = "{% trans "Failed to get upload url" %}";
                    }
                });
                return false;
            }
        })
        .bind('fileuploadprogressall', function (e, data) {
            total_progress.html(parseInt(data.loaded / data.total * 100, 10) + '% ').removeClass('hide');
            //console.log(parseInt(data.loaded / data.total * 100, 10))
            if (data.loaded > 0 && data.loaded == data.total) {
                saving_tip.show();
            }
        })
        .bind('fileuploadstop', function() {
            
        })
        // after tpl has rendered
        .bind('fileuploadcompleted', function() { // 'done'
            if ($('.files .cancel', popup).length == 0) {
                saving_tip.hide();
                total_progress.addClass('hide');
                fu_status.html(fu_status_.complete);
            }
            //setTimeout(function() { location.reload(true); }, 4000);
        })
        .bind('fileuploadfailed', function(e, data) { // 'fail'
            if ($('.files .cancel', popup).length == 0) {
                cancel_all_btn.addClass('hide');
                close_icon.removeClass('hide');
                total_progress.addClass('hide');
                saving_tip.hide();
                if (data.errorThrown == 'abort') { // 'cancel'
                    fu_status.html(fu_status_.canceled);
                } else { // 'error'
                    fu_status.html(fu_status_.failed);
                }
            }
        });

        // Enable iframe cross-domain access via redirect option:
        popup.fileupload(
            'option',
            'redirect',
            window.location.href.replace(/\/repo\/[-a-z0-9]{36}\/.*/, '{{ MEDIA_URL }}cors/result.html?%s')
        );
    });
});