You can mix even perl (with eperl), but it's generally a bad practice.
You should think through the following:
- Is your data to be indexed by Google?
- Is this a webpage or an application?
If it's an application, which won't be indexed by Google, grab JavaScript, CoffeeScript, Dart or Flash, and write a standard MVC application, with your server providing the backend in form of JSON-based services. It's just way more easier to think this way and still deal with application-level complexity.
If this has to be indexed by google, and/or it's a webpage, then build a WebMVC webpage, with templates, in Spring (java), Ruby on Rails (ruby), Django (python), Symfony (php), Catalyst Framework (perl), whatever. It's easier to accommodate data changes usually with such.
Both of these solution scale considerably.
Remember, every application started small.