_user.html.erb

<% content_for :head do %>
  <script>
    $('editable_link').click(function() {
      $('#editable_form').html( "<%= escape_javascript( raw render :partial => 'users/info_form') %>" );
    });
    </script>
<% end %>
<ul>
  <li>Login: <%= @user.login %></li>
  <li>Name: <%= @user.name %></li>
</ul>

<% if @user.info.blank? %>
  <%= link_to "Click to edit your user information", '#', :class=> 'editable_link' %>
  <div id="editable_form">
  </div>
<% else %>
  <%= @user.info %>
<% end %>

<%= link_to "Edit user", edit_user_path(@user), :remote => true %>