my wordpress ad switch javascript

wp_ad_switch.js

(function() {
  var metas = document.getElementsByTagName('head')[0].getElementsByTagName('meta');

  for (var index = 0; index < metas.length; index++) {
    if (metas[index].name === 'keywords' && metas[index].content.indexOf('技術系') !== -1) {
      console.log('技術記事');
      break;
    }
  }

  console.log(index, metas.length);
  if (index === metas.length) {
    console.log('その他');
  }
})();