http://www.google.com/trends/explore#q=Perl%2C%20JavaScript&...
And they both have a similar decline.
http://www.google.com/trends/explore#q=ada%2C%20JavaScript&c...
http://www.google.com/trends/explore#q=JavaScript%2C%20jquer...
The absolute decline looks similar but given javascript's higher starting value the relative decline is much less.
http://www.google.com/trends/explore#q=ada%2C%20JavaScript&c...