page rendering and drop down onchange event

hi,

I want to display a subject drop down list and when i select some option
from
the drop down list i want to display all the questions under that
selected
category in the "SAME PAGE" and also get a form to add new questions in
the same page.

eg ..

<%= collection_select(:question,:subject_id ,@subject, :id, :name) %>

when i choose a subject i should, display all the questions under that
subject in the same page and a text box to add new quesions too in the
same page.I am new to rails.Can anyone please help me
out..

Will page rendering partial help in any way?

Thanks in advance