code: def get_js(self):
          
          js_file = os.path.join(self.theme_dir, 'js', 'slides.js')
  
          if not os.path.exists(js_file):
              js_file = os.path.join(THEMES_DIR, 'default', 'js', 'slides.js')
  
              if not os.path.exists(js_file):
                  raise IOError(u"Cannot find slides.js in default theme")
          with codecs.open(js_file, encoding=self.encoding) as js_file_obj:
              return {
                  'path_url': utils.get_path_url(js_file, self.relative),
                  'contents': js_file_obj.read(),
              }
docs: Fetches and returns javascript file path or contents, depending if
              we want a standalone presentation or not.