JSFiddle - React, Tailwind, and code Playground

by Сергей Тарасевич

JavaScript

var Year = 2000,
     Month = 2;
 var DaysCount = new Date(Year, Month, 0).getDate();

 alert("всего дней:  " + DaysCount);

 var nD = new Date(),
     dd = nD.getMonth();

 alert("сейчас месяц :  " + dd);