ruby on rails - Uploading files using remote:true and remotipart + carrierwave gems -

i want make remote file upload via remotipart + carrierwave. problem upload works, seems uploaded usual html. or uploaded via ajax, appropriate js file not called. have form_for remote:true, , corrseponding controller method create. since form submitted js, create.js.erb used.

<% if @syllabus.errors.present? %>   $('#syllabus-errors').html('<%= escape_javascript(render 'layouts/error_messages', object: @syllabus)   %>');  <% else %>   alert("ds");   $('#modal-body').html(<%= escape_javascript(render 'layouts/thanks')   %>);   $('#syllabus-errors').html(""); <% end %> 

logs show this:

 (0.1ms)  begin transaction    (0.1ms)  rollback transaction   rendered layouts/_error_messages.html.erb (1.0ms)   rendered syllabuses/create.js.erb (12.0ms) 

it kinda strange error_messages rendered earlier create.js.erb, error_messages being rendered inside create.js.erb.

i resolved problem adding if:

<% if remotipart_submitted? %>    <% else %>    <% end %>

don't know why didn't work without it.