https://amola.ru/06-18/js/langVars.js

1var langVars = {};
2var lang = 'ru';
3
4function initLangVars(data) {
5    setLanguage();
6
7    if (data.length === 0) {
8        return false;
9    }
10    langVars = objExtend(langVars, data);
11}
12
13function objExtend(obj, src) {
14    Object.keys(src).forEach(function (key) {
15        obj[key] = src[key];
16    });
17
18    return obj;
19}
20
21function setLanguage() {
22    localStorage.setItem('lang', $('head').data('lang'));
23}
24
25$(document).ready(function () {
26    setLanguage();
27});