<div class="box-center text-center">
 	<header class="box-text">
 		<p class="info-text margin-0">Let's count them up!</p>
 	</header>
 	<main class="box-number">
 		<p class="number-text margin-0" id="js-number"></p>
 	</main>
 </div>
/* Helpers */

.text-center {
	text-align: center;
}

.margin-0 {
	margin: 0;
}

/* Others */

body {
	position: relative;
	height: 100vh;
	margin: 0;
}

.box-center {
	width: 200px;
	text-align: center;
	position: absolute;
	left: 50%;
	top: 50%;
	-webkit-transform: translateX(-50%) translateY(-50%);
	transform: translateX(-50%) translateY(-50%);
}

.box-text {
	background-color: #000;
	line-height: 50px;
}

.box-number {
	background-color: #008100;
	line-height: 150px;
}

.info-text {
	color: #fff;
	font-size: 12px;
}

.number-text {
	color: #fff;
	font-size: 90px;
}
/**
	Increase number
**/
const increaseNumber = () => {
	let counter = 0;
	const numberElement = document.getElementById("js-number") || {};

	setInterval(function startCount() {
		counter < 99 ? (numberElement.innerHTML = ++counter) : (counter = 0);
	}, 1000);
};

window.addEventListener("load", increaseNumber);
View Compiled

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.