W3Schools Tryit Editor

<!DOCTYPE html>
<html>

<head>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta content="text/html; charset=iso-8859-2" http-equiv="Content-Type">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/5/w3.css">
<style>
.mySlides {display:none;}
</style>
</head>

<body>

<h2 class="w3-center">Automatic Slideshow</h2>

</body>
</html>

​x
 
<!DOCTYPE html><html>​<head><title>W3.CSS</title><meta name="viewport" content="width=device-width, initial-scale=1"><meta content="text/html; charset=iso-8859-2" http-equiv="Content-Type"><link rel="stylesheet" href="https://www.w3schools.com/w3css/5/w3.css"><style>.mySlides {display:none;}</style></head>​<body>​<h2 class="w3-center">Automatic Slideshow</h2>​<div class="w3-content w3-section" style="max-width:500px">  <img class="mySlides" src="img_la.jpg" style="width:100%">  <img class="mySlides" src="img_ny.jpg" style="width:100%">  <img class="mySlides" src="img_chicago.jpg" style="width:100%"></div>​<script>var myIndex = 0;carousel();​function carousel() {  var i;  var x = document.getElementsByClassName("mySlides");  for (i = 0; i < x.length; i++) {    x[i].style.display = "none";    }  myIndex++;  if (myIndex > x.length) {myIndex = 1}      x[myIndex-1].style.display = "block";    setTimeout(carousel, 2000); // Change image every 2 seconds}</script>​</body></html>​