Future:

onclick javascript migth be able to change color of the button with my fuction

https://www.w3schools.com/tags/tryit.asp?filename=tryhtml5_ev_onclick3

styhled button https://www.w3schools.com/tags/tryit.asp?filename=tryhtml_button_css

buttons css https://www.w3schools.com/howto/howto_css_button_group.asp

also usinjg check boxes

multiple buttons selection in a group

radio buttons where select only one from a group

notify mutliple days problem before entering add event, when enter mulitple day, and when saving

use buttons, only on ina table, or mupliplcselection

onchange

onclick

Single left click to select or deselect a specific date, such as the Tenth of March or the 15th of June.

Double left click on a specific date of a month, such as the Tenth of March , to select ALL the 10th days of the months.

Single right click on the day of the week (S=Sunday M= Monday... F=Friday) to then select from a popup a repeating dates for that day of the week: All Sundays, Second Tuesdays, First Fridays).

Single right click on a date of the year (Tenth of March or the 15th of June) will pop up holidays. Left click on the holiday to be associated with that Date of the year. For example December 20th might be associated with Xmas holiday. Or July 3rd will be associated with Independence day events.