Rails - Mar 2006 - HELP: Rails / Ajax with 3 Drop down lists (see code)

Hi All,
I have successfully implemented a two tier drop down lost with rails. 
However I''m stumped on how to make a third tier. For example: The form 
has three select lists; Catagory, Subcatagory and Make

User Experience Desired:

1. On page load a Catagory Select List shows a list of Catagories from 
the database. example:
Portable Electronincs
Laptops
etc.

2. Upon select of Catagory (above) subcatagory select list is updated
<assuming Portable Electronincs selected above the result maybe>

Digital Camera
MP3 Player
etc..

3. Upon select of Subcatagory (above) Make select list is updated
<assuming MP3 player selected>
Apple
Creative labs
Sony
etc.

I have Catagories and Subcatagories complete using an observer (see 
below.) However I cannot get a second observer to trigger on the 
subcatagory selection. Is it a DOM issue? Is the Subcatagory select list 
once filled identified by some other name?

-JC

The code thus far:

THE CONTROLLER

  def lookup_subcats
    @subcatagories = 
Subcatagory.find_all_by_catagory_id(@params[:catagory_id]).collect 
{|subc| [subc.subcatagory, subc.id]}
    render :inline => "<%= select ''tag'',
''subcatagory_id'',
@subcatagories, {:selected => @subcat_count } %>"
  end

  def lookup_makes
    @subcat = (@params[:subcatagory_id])
    @makes = @subcat.makes.find_all_by_make_id.collect {|m| [m.make, 
m.id]}
    render :inline => "<%= select ''tag'',
''make_id'', @makes, {:prompt =>
true } %>"
  end


THE FORM:
<p><%= select ''tag'', ''catagory_id'',
@catagory_list, {:selected => 13 }
%></p>

<p>
<div id="subcatagory_container">
	<%= select ''tag'', ''subcatagory_id'', {
:Subcatagory => ''disabled'' } %>
</div>
</p>

<p>
<div id="make_container">
	<%= select ''tag'', ''make_id'', { :Make
=> ''disabled'' } %>
</div>
</p>

<%= observe_field(
	:tag_catagory_id,
	:update => :subcatagory_container,
	:url => { :action => :lookup_subcats },
	:with => "''catagory_id=''+escape(value)") %>

<%= observe_field(
	:tag_subcatagory_id,
	:update => :make_container,
	:url => { :action => :lookup_makes },
	:with => "''subcatagory_id=''+escape(value)")
%>

-- 
Posted via http://www.ruby-forum.com/.

Additional note for those looking at the code...(and other curious 
newbie like me)
The relationship between subcatagories and makes is many-to-many. This 
is because HP or Canon for example is a make that can be found in many 
subcatagories.

-- 
Posted via http://www.ruby-forum.com/.

JC wrote:
> Additional note for those looking at the code...(and other curious 
> newbie like me)
> The relationship between subcatagories and makes is many-to-many. This 
> is because HP or Canon for example is a make that can be found in many 
> subcatagories.
Is there a DOM browser or doc I can read on Prototype?

-- 
Posted via http://www.ruby-forum.com/.

JC wrote:
> JC wrote:
> 
>>Additional note for those looking at the code...(and other curious 
>>newbie like me)
>>The relationship between subcatagories and makes is many-to-many. This 
>>is because HP or Canon for example is a make that can be found in many 
>>subcatagories.
> 
> 
> Is there a DOM browser or doc I can read on Prototype?
> 
The docs that I use are here:

http://www.sergiopereira.com/articles/prototype.js.html

-- 
Alex

I tried to implement something similar but I found that it doesnt work in IE
at all.

IE does not support writing the innerHTML to a select box, so any ajax call
to populate a select box does not do anything.

If you come up with a way to overcome this I would be interested.

Cheers

On 3/30/06, Alex Young <alex@blackkettle.org>
wrote:
>
> JC wrote:
> > JC wrote:
> >
> >>Additional note for those looking at the code...(and other curious
> >>newbie like me)
> >>The relationship between subcatagories and makes is many-to-many.
This
> >>is because HP or Canon for example is a make that can be found in
many
> >>subcatagories.
> >
> >
> > Is there a DOM browser or doc I can read on Prototype?
> >
> The docs that I use are here:
>
> http://www.sergiopereira.com/articles/prototype.js.html
>
> --
> Alex
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
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