function SimpleEncode(text) {
    var retval = ""; /* the function will return this string */;
    for (i = 1; i < (text.length + 1); i++) {
        k = text.charCodeAt(i - 1);
        if (k >= 97 && k <= 109) {
            k = k + 13;
        } else
            if (k >= 110 && k <= 122) {
                k = k - 13;
            } else
                if (k >= 65 && k <= 77) {
                    k = k + 13;
                } else
                    if (k >= 78 && k <= 90) {
                        k = k - 13;
                    }
        retval = retval + String.fromCharCode(k);
    }
    return retval;
}