Rot = {
map: null,

convert: function(a) {
Rot.init();

var s = "";
for (i=0; i < a.length; i++) {
var b = a.charAt(i);
s += ((b>='A' && b<='Z') || (b>='a' && b<='z') ? Rot.map[b] : b);
}
return s;
},

init: function() {
if (Rot.map != null)
return;

var map = new Array();
var s = "abcdefghijklmnopqrstuvwxyz";

for (i=0; i<s.length; i++)
map[s.charAt(i)] = s.charAt((i+2)%26);
for (i=0; i<s.length; i++)
map[s.charAt(i).toUpperCase()] = s.charAt((i+2)%26).toUpperCase();

Rot.map = map;
},

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