drupal 的 cookie中 has_js 的意思 得到 cookie 有大用

/**
 * Initiate the batch processing
 */
function _batch_start() {
  // Choose between the JS and non-JS version.
  // JS-enabled users are identified through the 'has_js' cookie set in drupal.js.
  // If the user did not visit any JS enabled page during his browser session,
  // he gets the non-JS version...
  if (isset($_COOKIE['has_js']) && $_COOKIE['has_js']) {
    return _batch_progress_page_js();
  }
  else {
    return _batch_progress_page_nojs();
  }
}