brilliant! I'm impressed. Thank you!

By the way if you run it on 5.005 or thereabouts, you get an error :

Can't use subscript on split at ./obf.pl line 18, near "3]"<br>
  (Might be a runaway multi-line // string starting on line 16)<br>
Can't use subscript on split at ./obf.pl line 22, near "4]"<br>
[download]

It's fine on 5.8.5 though