read text field value in controller

Hi, i'm newbie with rails

i'm try to pass the value of a text_field to the controller without a
submit all form.

this is the html.erb code

       <% j = rel_issue.journals.find(:last, !:notes.nil?)
          unless j.nil?
            if j.notes.nil? %>

                  <p><%= text_field :testo, %></p>

                <% else %>




   <td class="buttons">

      <%if rel_issue.status && !rel_issue.status.is_closed?%>

       <%= link_to_remote(image_tag('link_break.png'),
            {:url => {:controller => 'deda_roadmap', :action => 'evade',
:id =>, :project => @project}},
            :submit => 'testo_', :method =>
:post,:title => l(:label_evasion)) %>

            <% end %>

and this the controller code:

def evade
    issue= Issue.find_by_id(params[:id])
   parametro = "testo_"
    testo_nota = params[parametro]
    if !testo_nota.nil?

testo_nota is nil in controller and i don't know why.

thanks for help.

Have a look at the Rails Guide on debugging, it will show you
techniques that you can use to debug the code and work out where it is
going wrong.