ActionController::UnknownFormat Error for only format.js

I am simply using -

respond_to do |format|
    format.js
end

in my create action. Don't know why but i am getting an the UnknownFormat error. The error is gone if i put in both "format.html" and "format.js". But i want to stay in the same page and make an ajax call. I have gone through like 5 pages of google search results for every possible search and still nothing works for me. Can anyone help me out here?

My form is like this -

<%= form_for [:home, Photo.new], remote: true, :html => {:id => "new-photo-form"} do |f| %>

    <div id="upload-field">
        <%= f.file_field :image %>
    </div>

    <%= f.hidden_field :album_id, :value => album.id %>

    <div id="photo-add-link">
        <%= link_to 'Add Selected Images', '#', remote: true, :onclick => "$('#new-photo-form').submit()" %>
    </div>

<% end %>