AJAX/RJS issue: observe_form not passing in form params

I’m having a problem with an AJAX form. I currently have a working
version as follows:

In my _picker.rhtml partial I have:

<%= observe_form “picker_form”, :update => “frame_picker” ,
:loading_text => “Retrieving price…”,
:complete => visual_effect(:highlight,
“picker_live_price”, { :startcolor => “’#9b3801’”, :endcolor =>
“’#f0c18e’”, :duration => 0.5 }),
:url => { :controller => ‘store’,
:action => “update_picker” } %>

In my store_controller.rb controller I have:

def update_picker
@frame = Frame.find(:first, :conditions => [“category = :category”,
@quantity = params[:picker_quantity]
render :partial => ‘/store/picker’

If I inspect the params array in the controller, it looks like:
{“action” => “update_picker”, “frame” => {…}, “controller” => “store”}

This is all good and it works. However, for some usability reasons, I
want to change this to use RJS. So, I’ve done the following:

In the partial, I removed the :update and :complete pieces of the
observe_form call that will now be handled by the rjs template:

<%= observe_form “picker_form” :loading_text => “Retrieving price…”,
:url => { :controller => ‘store’, :action
=> “update_picker” } %>

In the controller, I removed the render call:

def update_picker
@frame = Frame.find(:first, :conditions => [“category = :category”,
@quantity = params[:picker_quantity]

I added the update_picker.rjs rjs template:

page[:frame_picker].replace_html :partial => ‘picker’
page[:picker_live_price].visual_effect :highlight, :startcolor =>
“’#9b3801’”, :endcolor => “’#f0c18e’”

This does not work - I get an error on the Frame.find line in the
controller’s ‘update_picker’ action, because params[:frame] is nil. If I
inspect the params array, it looks like: {“action” => “update_picker”,
“controller” => “store”}. Notice that the frame key and values are no
longer there.

So, the problem appears to be that the form values are not getting
passed through from the observe_form command to the controller in this
second version. What have I done to account for the observe_form command
changing what it is passing through to the controller?

NOTE: The first field in my form is a radio button - does that make any kind of difference?

I would appreciate any help.

Through some further research, I’ve discovered that adding

:with => "value=value"

to the observe_form call solves the problem:

Anyone know why? Is this a rails bug?


I have a similar problem. My form uses 3 fields: 2 selects and a text

when I look at the params, I get the updated version of the text input
but not for the selects. For these, I keep getting the last option in
the list what every I do.

I tried the :with thig and it didnt change anything… anyone has an


I too have been hitting the problem that if you omit the :updated
option in the observe_form or observe_field method, then no parameters
are sent.

An example of the js with an update option included: (note

new Form.EventObserver(‘firstname’, function(element, value) {new
Ajax.Updater(‘updated_names’, ‘/customer/live_lookup’,
{asynchronous:true, evalScripts:true, parameters:value})})

If the :update is removed you get (note missing params):

new Form.EventObserver(‘firstname’, function(element, value) {new
Ajax.Request(’/customer/live_lookup’, {asynchronous:true,

Like you, I had been trying to use : with but was getting curious
results. Thanks for your solution :with=>‘valjue=value’ works a
treat, although I dont understand why. The js it produces is:

new Form.EventObserver(‘firstname’, function(element, value) {new
Ajax.Request(’/customer/live_lookup’, {asynchronous:true,
evalScripts:true, parameters:value=value})})

In fact I cannot understand the api explanation of :with. I get the
gist of what it does, but cannot fathom exactly how to use it. Can
anyone offer an improved explanation of how to use :with ?

Thanks Tonypm

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