jquery-file-upload

File upload form

  <%= form_for [@project, attachment], :html => {:id=>"fileupload", :class => type } do |f| %>
    <%= hidden_field_tag 'attachment_type', type %>
    <%= hidden_field_tag 'project_id',  project_id %>
    <span class="file-upload button">
    <span>Attach a File</span>
      <%= f.file_field :path %>
    </span>
    <table id="results"><tbody class="files"></tbody></table>
  <% end %>

jquery-file-upload initalization

    $(function () {
        // Initialize the jQuery File Upload widget:
        $('#fileupload.<%= type %>').fileupload({
          autoUpload: true,
          dataType: 'json'
        }).bind('fileuploadalways', function (e, data) {
              window.showQuickForm();
          }).bind('fileuploadcompleted', function (e, data) {
             // the current variable points to the hidden field that is used in
             // the issues form to send relevant data to the issues create action
             var current = $("<%= field_id %> input#attach_list").attr("value");
              $.each(data.result, function (index, file) {
                  // if the field is empty, set the value of the field to the uploaded's file name
                  if (current =="") {
                    current = file.id;
                  } else {
                  // if it's not empty, append the file name to the already existing values
                    current += "," + file.id;
                  }
              });
              $("<%= field_id %> input#attach_list").attr("value", current);
          });
    });