JSFiddle - React, Tailwind, and code Playground

JavaScript

var tarih1=new Date();
var tarih2=new Date('1/1/2011');

var y1=tarih1.getFullYear();
var y2=tarih2.getFullYear();

var ayFark=(tarih1.getMonth() + y1*12)-(tarih2.getMonth() +y2*12);

alert(ayFark+".jpg");