Currently if you use the :popup => 'force' option the form will not work with javascript disabled because the readonly attribute is in the html. I went ahead and forked the project and added a :support_no_js => true option that uses javascript to set the entry field to readonly rather than in the html so that the entry field is still editable for user's without javascript.

http://github.com/jfredson/calendar_date_select/tree/master

Feel free to adopt/modify/ignore as you see fit.

Thanks for a great gem.

I have a problem passing custom :index to fields_for, like
<%= f.fields_for :item, item, :index => 'someindex' do |fields| %>
for all fields it works fine except calendar_date_select

If I pass :index to calendar_date_select it works fine:
<%= fields.calendar_date_select :date, :index => 'someindex' %>