function setLanguageCookie(lang) {
    /* 1000 ms x 60 sec x 60 min x 24h = 1 day */
    var expires = 1000 * 60 * 60 * 24 * 30;
    var today = new Date();
    var expires_date = new Date( today.getTime() + expires );

    document.cookie = "chosenLanguage=" + escape( lang ) +
                      ";expires=" + expires_date.toGMTString();
}