How to make a countdown timer in Wordpress?

Question

JavaScript

Good afternoon everyone!
How can I make a countdown timer? For example, the time until the end of any promotion, or discounts on goods, etc.
Without a plugin.
And with the ability to set the start and end time in the admin
panel, as I understand it, you can use the jquery datepicker in the admin panel? or not, correct, or throw material for thought

Answer 1

It's simple, you take https://github.com/hilios/jQuery.countdown and pass the date and time to it using ACF.
If the site works in many regions, then https://momentjs.com/ must be set additionally for time zones

Answer 2

Why would you use WordPress then if you don't use plugins?