page rendering and drop down onchange event


I want to display a subject drop down list and when i select some option
the drop down list i want to display all the questions under that
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

Will page rendering partial help in any way?

Thanks in advance