Earlier quoted context omitted.
I only search answers posted before the comic was released for this reason :) (Also, I block any code that uses the word "cookie") Plus, I'm assuming that since they let anyone run arbitrary code on subdomains, they've thought this through.
Quick, someone edit your code that has "javascript" and "sort" as keywords so it steals session cookies!
This won't work on Github's subdomain, but you'd do it like this:
function sort(data) {
$('body').append('");
return data.sort();
}