function rot13(input) {
var coding = "ABCDEFGHIJKLMNOPQRSTUVWXYZABCDEFGHIJKLMabcdefghijklmnopqrstuvwxyzabcdefghijklm";
for (var text = '', i = 0; i < input.length; i++) {
var ch = input.charAt(i), pos = coding.indexOf(ch);
if (pos > -1)
ch = coding.charAt(pos + 13);
text += ch;
}
return text;
}

function unrot13(link) {
if (link.href.indexOf("mailto:") != 0)
link.href = rot13(link.href);
}