Rot13 = {
    map: null,
    convert: function(a) {
        Rot13.init();
        var s = "";
        for (i=0; i < a.length; i++) {
            var b = a.charAt(i);
            s += ((b>='A' && b<='Z') || (b>='a' && b<='z') ? Rot13.map[b] : b);
        }
        return s;
    },
    init: function() {
        if (Rot13.map != null)
            return;
        var map = new Array();
        var s   = "abcdefghijklmnopqrstuvwxyz";
        for (i=0; i<s.length; i++)
            map[s.charAt(i)] = s.charAt((i+13)%26);
        for (i=0; i<s.length; i++)
            map[s.charAt(i).toUpperCase()] = s.charAt((i+13)%26).toUpperCase();
        Rot13.map = map;
    },

    write: function(a) {
        document.write(Rot13.convert(a));
    }
}