subscriber.js

var subscriberElement = document.getElementById('c4-primary-header-contents').getElementsByClassName('yt-subscription-button-subscriber-count-branded-horizontal yt-uix-tooltip')[0];
var i = another = Number(subscriberElement.innerHTML.replace(",",""));
var count = setInterval(function(){
	counter(i);
	i += 9;
	if(i >= another+10000){
		clearInterval(count);
		}
	},10);
function counter(num){
	subscriberElement.innerHTML = String(num).replace(/(\d)(?=(\d\d\d)+(?!\d))/g,'$1,');
}