How to transform my html form into a rails 3 form

Thank you for your detailed answer!

I started with Rails 3, so there is no “old” Rails 2 code in it. As I
know Rails 3 comes out-of-the-box configured with prototype, right? So
yes I have prototype installed.

And yes you are right I meant javascript helpers (not JAVA), like
this:
<%= button_to ‘Destroy’, product, :confirm => ‘Are you sure?’, :method
=> :delete %>

But I meant JRails not JRuby! It could be found here:

Here is the Railscast that is showing JRails:

It should just add JQuery to your Rails App and the standard OOTB
prototype javascript helpers should still work, but I haven’t tried
that.

So if a install the “jquery-rails” gem like you mentioned, are the
prototype helpers still working?