Toggle html[lang=___] script

gistfile1.js

var DEFAULT_VALUE = 'ru-ru';
function toggle (language) {
  language = (typeof language === 'undefined') ? DEFAULT_VALUE : language;
  
  var currentLang = $('html').attr('lang');
  if (currentLang === 'en') {
    $('html').attr('lang', language);
  }else if (currentLang === language) {
    $('html').attr('lang', 'en');
  } else {
    //If its not en or default, lets toggle back to en, so the loop is loopie
    $('html').attr('lang', 'en');
  }
  console.log('currentLang: ', $('html').attr('lang'));
}
toggle();