jQuery.DatePicker | Lightweight and customizable datepicker | Datepicker library

I've question why Input onchange in JS doesn't work in my code. if I select 1st date it doesn't call function onchange="myFunction2(this.value)" but in the 2nd form it does. First function is working only if I keep pressing enter. Also check console.log and you'll see that 1st function isn't working

JSFiddle

With the code below, I'm trying to gray out 21/12/2020 because we don't ship until Tuesday(22/12/2020). I cannot find what is wrong in the code below. Please point out the error in the code that might be causing it not to work.

I am using JQuery-UI datepicker and Laravel-5.8

From the Controller, I sent NationalHoliday as JSON to the view

Please can someone please explain how this code works? It's a trivial piece of code but I don't understand/appreciate how the Option

beforeShowDay

, that calls a function works.

The DisableDates Option calls function DisableDates(date) (that seemingly) takes in a date parameter - and I can't understand how this date parameter is being passed?

I need to exclude Monday and Tuesday from a datepicker throughout the year, but need to allow this during the holiday season for 2020-12-21 and 2020-12-22.

How could I counter the day != 1 && day != 2 and only use this if not one of the above dates?

I want to disable days dynamically by using array,

replacing the code :

I would like to skip disabled dates.

working: The code can skip the dates that are from the array:

I'm trying to take dates from a date field in a custom post type in wordpress and then transfer the dates into an array. Then that array is converted to a js object. That js object is used in a datepicker with beforeShowDay, but it is not working. I get the datepicker but no dates are unavaible.

If I do:

Bootstrap datePicker allows me to pass a parameter to disabled an specific day of the week. Like this: