How do I create an interactive form with Simple Form? - ruby-on-rails

Question

I have a model (Listing) that has many, many attributes (say 25).
I would like to create an AJAX form that is dynamic based on the input in the form.
Meaning that if a user chooses type=b, they will see other fields that they should see and not ones they shouldn't.
Ideally they should load immediately, with the right content from the db - i.e. in an AJAXy way.
What's the best way to approach this?
Thanks.
Edit: Here is an example of my _form.html.erb. You will notice that I have included 2 if statements that indicate which fields should show if the property_type value chosen is one of those specified:
<%= simple_form_for(#listing) do |f| %>
<%= f.error_notification %>
<div class="form-inputs">
<%= f.input :headline %>
<%= f.input :price %>
<%= f.association :property_type %>
If property_type == "coop"
<%= f.input :maintenance %>
<%= f.input :coop_deductible %>
<%= f.input :flip_tax %>
if property_type == "condo"
<%= f.input :common_charges %>
<%= f.input :taxes %>
</div>
<div class="form-actions">
<%= f.button :submit %>
</div>
<% end %>
Edit 2:
This is the Rails form helper that I used - powered by the gem Simple_Form:
<%= simple_form_for #listing, :defaults => { :wrapper_html => { :class => 'form-horizontal' } } do |f| %>
<%= f.error_notification %>
<fieldset>
<%= f.association :listing_category, :label => "Category: ", :label_html => { :class => "control-label"}, :wrapper_html => { :class => "controls"} %>
<div style="display: none;" data-show-for="Exclusive">
<%= f.association :listing_type %>
<%= f.association :user %>
<%= f.association :boro %>
</div>
<div style="display: none;" data-show-for="Open">
<%= f.association :neighborhood %>
<%= f.association :building %>
<%= f.association :term %>
<%= f.association :property_type %>
</div>
<div class="form-actions">
<%= f.button :submit, :class => "btn btn-primary" %>
<!-- <button type="submit" class="btn btn-primary">Save and Continue</button>
<button type="reset" class="btn">Cancel</button> -->
</div>
</fieldset>
<% end %>
This is the HTML it produced:
<form accept-charset="UTF-8" action="/listings" class="simple_form new_listing" id="new_listing" method="post" novalidate="novalidate"><div style="margin:0;padding:0;display:inline"><input name="utf8" type="hidden" value="✓" /><input name="authenticity_token" type="hidden" value="1oDfg41Wx/SiPCsvf4qTAcxhFUGSNlhlLfkMy8nHW1E=" /></div>
<fieldset>
<div class="control-group select optional controls"><label class="select optional control-label control-label" for="listing_listing_category_id">Category:</label><div class="controls"><select class="select optional" id="listing_listing_category_id" name="listing[listing_category_id]"><option value=""></option>
<option value="1">Exclusive</option>
<option value="2">Open</option></select></div></div>
<div style="display: none;" data-show-for="Exclusive">
<div class="control-group select optional form-horizontal"><label class="select optional control-label" for="listing_listing_type_id">Listing type</label><div class="controls"><select class="select optional" id="listing_listing_type_id" name="listing[listing_type_id]"><option value=""></option>
</select></div></div>
<div class="control-group select optional form-horizontal"><label class="select optional control-label" for="listing_user_id">User</label><div class="controls"><select class="select optional" id="listing_user_id" name="listing[user_id]"><option value=""></option>
<option value="1">First User</option>
<option value="2">Second User</option>
<option value="3">Third User</option>
<option value="4">Fourth User</option>
<option value="5">Fifth User</option></select></div></div>
<div class="control-group select optional form-horizontal"><label class="select optional control-label" for="listing_boro_id">Boro</label><div class="controls"><select class="select optional" id="listing_boro_id" name="listing[boro_id]"><option value=""></option>
<option value="1">Brooklyn</option></select></div></div>
</div>
<div style="display: none;" data-show-for="Open">
<div class="control-group select optional form-horizontal"><label class="select optional control-label" for="listing_neighborhood_id">Neighborhood</label><div class="controls"><select class="select optional" id="listing_neighborhood_id" name="listing[neighborhood_id]"><option value=""></option>
<option value="1">Prospect Heights</option></select></div></div>
<div class="control-group select optional form-horizontal"><label class="select optional control-label" for="listing_building_id">Building</label><div class="controls"><select class="select optional" id="listing_building_id" name="listing[building_id]"><option value=""></option>
<option value="1">Trump Towers</option></select></div></div>
<div class="control-group select optional form-horizontal"><label class="select optional control-label" for="listing_term_id">Term</label><div class="controls"><select class="select optional" id="listing_term_id" name="listing[term_id]"><option value=""></option>
</select></div></div>
<div class="control-group select optional form-horizontal"><label class="select optional control-label" for="listing_property_type_id">Property type</label><div class="controls"><select class="select optional" id="listing_property_type_id" name="listing[property_type_id]"><option value=""></option>
<option value="1">Coop</option></select></div></div>
</div>
<div class="form-actions">
<input class="btn btn btn-primary" name="commit" type="submit" value="Create Listing" />
<!-- <button type="submit" class="btn btn-primary">Save and Continue</button>
<button type="reset" class="btn">Cancel</button> -->
</div>
</fieldset>
</form>
This is the JS that I included in my listing.js - which corresponds to the file that this form is on app/views/listings/new.html.erb
$(document).ready(function({
$('#listing_listing_category_id').on('change', function(){
var option = $(this).find(':selected');
$('[data-show-for]').hide(); //And maybe reset?
$('[data-show-for="+ option.text +"]').show()
});
});
When I chose the option I want, it doesn't show me the fields I want to see.

Answer 1

Personally I wouldn't use AJAX, just straight JS/JQuery to show/hide on click using data attributes.
See fiddle: http://jsfiddle.net/XnPZF/
First, add the data attributes to the sections you want to hide/show:
<div style="display: none;" data-show-for="coop">
<%= f.input :maintenance %>
<%= f.input :coop_deductible %>
<%= f.input :flip_tax %>
</div>
<div style="display: none;" data-show-for="condo">
<%= f.input :common_charges %>
<%= f.input :taxes %>
</div>
Then create a change event on the select:
$('#listing_property_type').on('change', function(){
var option = $(this).find(':selected');
$('[data-show-for]').hide(); //And maybe reset?
$('[data-show-for='+ option.text() +']').show()
});
For data-show-for, you can use Option text or value, just be sure to make sure the event knows which. If you plan to use this a lot of times, you could generalize it, but that would mean building your options.