code: function loadFiles(items, event) {
        if(!items.length){
          return; // nothing to do
        }
        $.fire('beforeAdd');
        var files = [];
        processCallbacks(
            Array.prototype.map.call(items, function(item){
              // bind all properties except for callback
              var entry = item;
              if('function' === typeof item.webkitGetAsEntry){
                entry = item.webkitGetAsEntry();
              }
              return processItem.bind(null, entry, "", files);
            }),
            function(){
              if(files.length){
                // at least one file found
                appendFilesFromFileList(files, event);
              }
            }
        );
      }
docs: process items to extract files to be uploaded
  @param  {File[]} items items to process
  @param  {Event} event event that led to upload