upload thru IFRAME

I created one Prototype helper.In that a method with following name is

def form_remote_tag_with_multipart_support(options = {}, &block)
   if options[:html][:multipart]
       uid = "a#{Time.now.to_f.hash.abs}"
       options[:html].merge!(:target => uid)
       iframe = capture_haml do
        haml_tag :iframe, :class => 'hidden', :id => uid, :name => uid,
:src => 'about:blank'
          url_for_options = options[:html].delete(:action) ||
          if block_given?
            haml_concat iframe
            form_tag url_for_options, options[:html], &block
              #{form_tag url_for_options, options[:html]}

on view I write
<%= form_remote_tag_with_multipart_support :service_list, :url=>
service_path, :method => :post do |f|>
<% render :partial=> "form" %>

its giving ActionView::TemplateError

What's the stack trace behind the error? For starters your helper
doesn't check that options[:html] exists, you're calling it with a
different number of parameters than you defined it with and you're
using <%= even though you're passing it a block.