Topic: How to load partials on a multiple page form in Rails

I have a website where users can register.  I have a registration form which consists of three partials (_step1.html.erb thru _step3.html.erb).

user.rb contains an array of the partial names and a method to go to the next step:

def current_step
  @current_step || steps.first
end

def steps
  %w[step1 step2 step3]
end

def next_step
  self.current_step = steps[steps.index(current_step) + 1]
end

The create action is what moves you to the next step:

def create
  @user = User.new(params[:user])
  @user.current_step = session[:user_step]
  @user.next_step
  session[:user_step] = @user.current_step
  render :new
end

The new.html.erb files renders the following partial when one clicks 'Next' on the form:

<%= form_for(@user, :html => { :class => "form-horizontal" }) do |f| %>
<div id="partial">
  <%= render @user.current_step, :f => f %>
</div>
<%= f.submit "Next", class: "btn btn-primary", :name => "next_button" %>

My question is how to get each partial to load using AJAX?  My idea is to do something like this:

$("#partial").html("<%= escape_javascript(render @user.current_step) %>");

But this doesn't work.  Any suggestions?