function getQueryVariable(key) {
var query = window.location.search.substring(1);
var vars = query.split('&');
for (var i = 0; i < vars.length; i++) {
var pair = vars[i].split("=");
if (decodeURIComponent(pair[0])== key) {
return decodeURIComponent(pair[1]);
}
}
}
var lang= getQueryVariable('lang');
console.log(lang);