function change_language(lang)
 {
    if (lang)
     {
         domain = location.href.substr(location.href.indexOf('://')+3);
         location.href = '/'+lang+domain.substr(domain.indexOf('/'));
     }
    else
     {
         domain = location.href.substr(location.href.indexOf('://')+3);
         path = domain.substr(domain.indexOf('/')+1);;
         location.href = path.substr(path.indexOf('/'));
     }

 }