Problem with ajax in date select - ruby-on-rails

Question

Excuse me, I am a newbie programmer in Rails.
I want use AJAX in a DATE SELECT. when I change the date, change the punitive ammount depends the result of method get_punitive (Model).
I use the next code in Controller, Model and View.However the event On change is not recognized. please you could help me.
Operations Model (partially)
def get_punitive(payment_date, expiration_date)
if payment_date > expiration_date
expiration_days= (payment_date - expiration_date).to_i
else
expiration_days = 0
end
punitive_ammount = (self.capital * (self.interest_rate_for_taker / 100.0) * expiration_days) / 30
# raise punitive_ammount.inspect
end
Operations Controller (partially)
def cancel
#operation = Operation.find(params[:id])
last_pagare = Pagare.find(:first, :conditions => "operation_id = #{#operation.id} AND state <> 'cancelled'")
#punitive_ammount = #operation.get_punitive(DateTime.now.to_date, last_pagare.expiration_date.to_date)
end
def update_payment_date
raise params.inspect
end
def submit_cancellation
#operation = Operation.find(params[:id])
ammount = params[:ammount]
punitive_ammount = (params[:punitive_ammount].blank?) ? 0 : params[:punitive_ammount]
payment_date = Date.new(params[:"payment_date(1i)"], params(:"payment_date(2i)"), params(:"payment_date(3i)"))
admin = User.find_by_login('admin')
if #operation.cancel(ammount, punitive_ammount, admin, payment_date)
respond_to do |format|
format.html { redirect_to(admin_operations_url) }
format.xml { head :ok }
end
else
#operation.errors.add_to_base("Los montos ingresados son invalidos")
render :action => 'cancel'
end
View of cancel
Cancelacion de Operaciones
<% form_for(#operation, :url => submit_cancellation_admin_operation_path) do |f| %>
<%= f.error_messages %>
<%= text_field_tag :a, :onClick => "javascript:alert('hola');" %>
<p>Fecha de Pago:<br/><br/>
<%= date_select("", :payment_date, {:start_date => Time.now, :onchange => remote_function(:url => {:controller => 'operations', :action => "update_payment_date"}, :with => "'payment_date='+value")}) %>
</p>
<p>Prueba
<%= collection_select "", :object, Operation.all, :id, :taker_id, { :onChange => "javascript::alert('hola');", :onClick => remote_function(:url => {:controller => 'operations', :action => "update_payment_date"}, :with => "'dgdfg='+value")} %>
</p>
<p>Monto a Cancelar (Mayor a cero):<br/><br/>
<%= text_field_tag :ammount , #operation.get_balance(#operation.interest_rate_for_taker) %>
</p>
<p>Monto punitorio:<br/><br/>
<%= text_field_tag :punitive_ammount, #punitive_ammount %>
</p>
<!--<p>Fecha de Pago:<br/><br/>
<%#= date_select("", :date, :start_year => Time.now.year-1, :default => Time.now) %>
</p>-->
<% %>
<p>
<%= f.submit 'Cancelar' %>
</p>
<% end %>

Answer 1

Hi format of date_select helper is
date_select(object_name, method, options = {}, html_options = {})
you have
<%= date_select("", :payment_date, {:start_date => Time.now, :onchange => remote_function(:url => {:controller => 'operations', :action => "update_payment_date"}, :with => "'payment_date='+value")}) %>
try
<%= date_select("", :payment_date, {:start_date => Time.now}, {:onchange =>"javascript::alert('hola');"}) %>
the same about collection_select
collection_select(object, method, collection, value_method, text_method, options = {}, html_options = {})
you have
<%= collection_select "", :object, Operation.all, :id, :taker_id, { :onChange => "javascript::alert('hola');", :onClick => remote_function(:url => {:controller => 'operations', :action => "update_payment_date"}, :with => "'dgdfg='+value")} %>
try
<%= collection_select "", :object, Operation.all, :id, :taker_id, {}, { :onChange => "javascript::alert('hola');"}%>