function swapLang(lang) {
    lang = '/' + lang + '/';
    currentLang = '';
    s = new String(location.href);

    if (s.indexOf('\/b5g\/') > 0) {
        currentLang = 'b5g';
        s = s.replace(/\/b5g\//g, lang);
    }
    if (s.indexOf('\/gbg\/') > 0) {
        currentLang = 'gbg';
        s = s.replace(/\/gbg\//g, lang);
    }
    if (s.indexOf('\/eng\/') > 0) {
        currentLang = 'eng';
        s = s.replace(/\/eng\//g, lang);
    }
    if (s.indexOf('\/txt\/') > 0) {
        currentLang = 'txt';
        s = s.replace(/\/txt\//g, lang);
    }
    
    location.href = s;
    
}