Using the JS and Functions route, the Year changes to 1819 upto 2119 as the yearRange is set to -200:+100″. Also since using a Child theme I copied the JS file in the Child theme’s folder under JS and I changed the get_template_directory_uri() to get_stylesheet_directory_uri().
I then checked the source code in the Dashboard and the required JS file was loaded.
So when I select a date, I can go from 1819 to 2119 not only that when I select the date and update the page the date changes to the current date.
Why won’t it save the selected date and then inserts the current date using the method suggested in the link above?