Real time form validation

Hello, I am stuck with a realtime form validation. I obtained information on how to build real time form validaion on:

http://blog.andyamiri.com/2008/05/ajax-form-validation-for-rails.html

It has worked great.... but... until now I have not been able to validate a password confirmation field for the form. The problem is based on my limitation to modify the code to accept two different field values to validate. I would appreciate it very much if someone could help me. Thanks in advance.

Here is the code:

  def error_message_for(model, field, options = {})     options[:success_css_class] ||= 'success'     options[:error_css_class] ||= 'error'     options[:hint_css_class] ||= 'hint'     tag_id = "#{model}_#{field}_validator"     js = observe_field "#{model}_#{field}", :function =>       "new Ajax.Request(         '/usuario/validate?field=#{field}&value=' + value,         { method: 'get',           onSuccess: function(transport) {             element = document.getElementById('#{tag_id}');             var output = transport.responseText;             var css_class = '#{options[:error_css_class]}';             if (output.length == 0) {               output = '#{options[:success]}';               css_class = '#{options[:success_css_class]}'             }             element.innerHTML = output;             element.setAttribute('class', css_class);           }         }       );"     tag = content_tag :span, options[:hint], :id => tag_id, :class => options[:hint_css_class]     return tag + js   end

This "helper" triggers the observe_field for changes... when the field is changed it sends the "value" of the "field" to a function called "validate" which I show next:

def validate     field = params[:field]     user = User.new(field => params[:value])     output = ""     user.valid?     if user.errors[field] != nil       if user.errors[field].class == String         output = "#{user.errors[field].slice(2,100)}"       else         output = "#{user.errors[field].slice(2,100)}"       end     end     render :text => output end

which then returns the result and gets displayed on the view... I need to somehow add the "password_confirmation" field to the process so that I can then validate that it is equal to the password. Thanks again.