in reply to Perl vs. Javascript
I almost never use JavaScript except when I'm directly scripting effects for my browser of choice (IE). Trying to support more than one browser/OS/Version combination with JavaScript fails in spectacular ways.
If it's at all possible, JavaScript can greatly augment the client experience by providing instant feedback when entering data fields, and I'm considering dynamically created JavaScript for data entry forms that duplicates the logic from my Perl scripts (the Perl scripts operate on logic read from the database/a hash anyway).
For fancy stuff, there are great JavaScript libraries that (try to) insulate you from the nasty world of browser differences, like http://www.dynamicdrive.com/ or OverLib.
If you think it's absolutely necessary to have JavaScript, consider that you will block/annoy all those people who surf with JavaScript disabled (like me)...