code: def evaluate_js(script, uid='master'):
      
      escaped_script = 'JSON.stringify(eval("{0}"))'.format(escape_string(script))
      return gui.evaluate_js(escaped_script, uid)
docs: Evaluate given JavaScript code and return the result
      :param script: The JavaScript code to be evaluated
      :param uid: uid of the target instance
      :return: Return value of the evaluated code