W3Schools Tryit Editor

<!DOCTYPE html>
<html>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
body {
  font-family: Arial;
  margin: 0;
}

* {
  box-sizing: border-box;
}

img {
  vertical-align: middle;
}

/* Position the image container (needed to position the left and right arrows) */
.container {
  position: relative;
}

/* Hide the images by default */
.mySlides {
  display: none;
}

/* Add a pointer when hovering over the thumbnail images */
.cursor {
  cursor: pointer;
}

/* Next & previous buttons */
.prev,
.next {
  cursor: pointer;
  position: absolute;
  top: 40%;
  width: auto;
  padding: 16px;
  margin-top: -50px;
  color: white;
  font-weight: bold;
  font-size: 20px;
  border-radius: 0 3px 3px 0;
  user-select: none;
  -webkit-user-select: none;
}

/* Position the "next button" to the right */
.next {
  right: 0;
  border-radius: 3px 0 0 3px;
}

/* On hover, add a black background color with a little bit see-through */
.prev:hover,
.next:hover {
  background-color: rgba(0, 0, 0, 0.8);
}

/* Number text (1/3 etc) */
.numbertext {
  color: #f2f2f2;
  font-size: 12px;
  padding: 8px 12px;
  position: absolute;
  top: 0;
}

/* Container for image text */
.caption-container {
  text-align: center;
  background-color: #222;
  padding: 2px 16px;
  color: white;
}

.row:after {
  content: "";
  display: table;
  clear: both;
}

/* Six columns side by side */
.column {
  float: left;
  width: 16.66%;
}

/* Add a transparency effect for thumnbail images */
.demo {
  opacity: 0.6;
}

.active,
.demo:hover {
  opacity: 1;
}
</style>
<body>

<h2 style="text-align:center">Slideshow Gallery</h2>

function plusSlides(n) {
  showSlides(slideIndex += n);
}

function currentSlide(n) {
  showSlides(slideIndex = n);
}

​x
 
<!DOCTYPE html><html><meta name="viewport" content="width=device-width, initial-scale=1"><style>body {  font-family: Arial;  margin: 0;}​* {  box-sizing: border-box;}​img {  vertical-align: middle;}​/* Position the image container (needed to position the left and right arrows) */.container {  position: relative;}​/* Hide the images by default */.mySlides {  display: none;}​/* Add a pointer when hovering over the thumbnail images */.cursor {  cursor: pointer;}​/* Next & previous buttons */.prev,.next {  cursor: pointer;  position: absolute;  top: 40%;  width: auto;  padding: 16px;  margin-top: -50px;  color: white;  font-weight: bold;  font-size: 20px;  border-radius: 0 3px 3px 0;  user-select: none;