Rails AJAX remote: true with dynamic id

I implemented a basic AJAX Call in Rails, which is working fine with this:

index.html.erb

<a href="/days/new" data-remote="true" id="new_day_ajax">Add This day</a>

new.js.erb

$('#new_day_ajax').hide().after('<%= j render("form")%>');

The problem is I generate up to 31 a-tags like the above one on a single page with the following loop and the form will of course always show up at the first one, no matter which link I click:

end_date.downto(start_date).each do |date|
    [...]

To make the form show up at the clicked link I tried to generate the ids dynamically like so:

id="new_day_ajax_<%= date.strftime('%d') %>" <!-- i.e. new_day_ajax_07 -->

but now I don't know how to pass this dynamic id into the new.js.erb. How can I know the dynamic id inside of the javascript?

Thanks in advance!