Any web-framework worth its salt will have implemented this "context" issue somewhere away from your prying eyes and offer you a clean API where context is automatically taken care of. Catalyst springs to mind as a good example.

Of course the "context" issue has nothing to do with Perl or Java of AJAX or ..., it is just the way the web works and personally I rather have the context dealt with server side where I can control it rather than on the client's machine where Gods know what may have happened to it.