Why doesn't the script work in the pop-up window?

Question

JavaScript

The form opens in a modal window.
When the input is clicked, a class should be added.
So it works on the site, but not in the modal window.
Why?

Answer 1

bitvaextrasensov.tnt-online.ru

Answer 2

My psychic suggests that you hang the event before the element is created.
Use jQuery('parent static selector').on('event', 'selector', callback);

Answer 3

Question removed.
Changed to another script.