Need litle help in about form element

I am newbie to html forms elements. can someone please tell me how do I make <select /> option in a way when a user select product a, another question related to this product appears.

please see this form. When you select a product, another section related to this product appear

 

its javascript
im sorry, i dont understand javascript.. but i can code PHP, tell me if you need it in PHP... but it will refresh the page , then give another question related to that product.

 

thanks nastynappy, I can use php instead later. can you provide me details

thanks again

 

php will be doing this:
when someone will select a product, it will reload the page with new options for him