title: Is there a way to call a method on the data loaded into a form input in Rails? (Specifically a text_field)
body: <p>I'm using Rails 3.0.5, and for the reasons specified in <a href="https://stackoverflow.com/questions/6554075/rails-config-time-zone-doesnt-apply-to-datetime-data-loaded-into-a-text-field">this question</a>, I need to call a utc_to_local method on the text_field input for a datetime.</p>
  
  <p>I've tried calling the method in various ways directly in the view (as a starting point), but I can't seem to find the magic mix (haven't called a method on a form field before).</p>
  
  <p>/events/edit.html.erb (full file):</p>
  
  <pre><code>&lt;h1&gt;Edit This Event&lt;/h1&gt;
  &lt;%= form_for(@event) do |f| %&gt;
      &lt;%= render 'fields', :f =&gt; f %&gt;
      &lt;div class="actions"&gt;
          &lt;%= f.submit "Update Event" %&gt;
      &lt;/div&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>events/_fields.html.erb (relevant lines only:)</p>
  
  <pre><code>&lt;div class="field"&gt;
      &lt;%= f.label      :time_start, "Start Time" %&gt;&lt;br /&gt;
      &lt;%= f.text_field  :time_start, :class =&gt; "datetimefield" %&gt;
  &lt;/div&gt;
  </code></pre>