Are you certain that the problem is with the Perl side of things? Does your page work without Javascript and does it output the expected HTML then?

I suggest you first debug the Perl side of things until your program outputs the appropriate headers and the appropriate HTML.

You can greatly clean up your returned Javascript by putting it into a separate file or at least using single quoted strings to eliminate all the backslashitis you need whenever a dollar sign is used.

Then I suggest that you investigate the $.load() method if Jquery, which would seem to do what your code does, replace some HTML by some other HTML returned from the server.