While JavaScript can help reduce overhead, you can not guarantee(unless you stop js'less people from using) people will use the javascript, and thusly you must do it in perl, that is if the client is gonna have any communication with the server, aside from requesting pages and providing %ENV vars ;-)

 
___crazyinsomniac_______________________________________
Disclaimer: Don't blame. It came from inside the void
perl -e "$q=$_;map({chr unpack qq;H*;,$_}split(q;;,q*H*));print;$q/$q;"