Why is the dropdown calendar not working in the Joomla 3 registration form?

Question

Joomla

Good afternoon! Site on Joomla 3. There is a registration form on the site alcopribor.ru/login/registration
There is a field "Date of birth" and a calendar icon. In theory, when you click on it, a dropdown datepicker should appear - however, nothing happens. This is implemented by the regular Joomla plugin "User - Profile", the path to it is \plugins\user\profile. The plugin's internal file fields\dob.php is responsible for the calendar and contains the class JFormFieldDob extends JFormFieldCalendar.
What needs to be done to make the drop-down calendar work when clicking on the icon? As far as I know, JFormFieldCalendar implements it - why might it not work in my case?

Answer 1

Try going through Firebug and reinstalling Joomla! Since I see you have a void in the button itself.

Answer 2

So emptiness is not yet a sign of a defect, maybe somewhere the handler for this button is hidden in the bowels of the system?
By the way, could you throw a link to an example of a site on Jumla with a working calendar so that I can compare?
Addendum: by the way, the handler is visible in the source code of the page (it does not have to be in the button code):

jQuery(document).ready(function($) {Calendar.setup({
// Id of the input field
inputField: "jform_profile_dob",
// Format of the input field
ifFormat: "%Y-%m-%d",
// Trigger for the calendar (button ID)
button: "jform_profile_dob_img",
// Alignment (defaults to "Bl")
align: "Tl",
singleClick: true,
firstDay: 1
});});