docs: def progress_bar_media():
      """
      progress_bar_media simple tag
  
      return rendered script tag for javascript used by progress_bar
      """
      if PROGRESSBARUPLOAD_INCLUDE_JQUERY:
          js = ["http://code.jquery.com/jquery-1.8.3.min.js",]
      else:
          js = []
      js.append("js/progress_bar.js")
          
      m = Media(js=js)
      return m.render()