Template and dynamic classes

[eluser]kostyak[/eluser]
Hi,Radou!
Answering on your questions, I can suggest you to use jQuery library for JS for both task:
>1/ How can I change the class dynamically on click
make function to remove class from the first <li> and put it to the appropriate <li>
>2/ How to load the main view without loading the page (ajax ?)
Make Ajax request through Jquery function load() and if success, than execute function from the first answer.