Ajax doesnt have to be comlicated, so check out TinyAJAX. Its a PHP implimentation that is usefull or simple AJAX elements.
“TinyAjax allows you to:

• AJAX enable your pages without having to write a single line of javascript
• Call PHP functions in classes or as separate functions, you can even extend TinyAjax by subclassing it
• Let your PHP-code set which elements to alter and with what using behaviours
• Integrate it with a template system (smarty-example included)
• Easily have gmail style “Loading” notification when AJAX-code is executing
• Use PHP-functions for both AJAX callback and regular code

You don’t have to write any javascript, but if you want you’re free to do so and you can mix as you want, use TinyAjax automatically generated code and your own existing scripts. You can also export global functions and a class-functions in the same page.”