Slideshow (from scratch)

the CSS code

* {
	box-sizing: border-box;
}

body {
	font-family: Verdana, sans-serif; 
	margin: 0;
}

.mySlides {
	display: none;
}

img {
	vertical-align: middle;
}
 
/* Slideshow container */
.slideshow-container {
	max-width: 1000px;
	position: relative;
	margin: auto;
}
 
/* Next & previous buttons */
.prev, .next {
	cursor: pointer;
	position: absolute;
	top: 50%;
	width: auto;
	padding: 16px;
	margin-top: -22px;
	color: white;
	font-weight: bold;
	font-size: 18px;
	transition: 0.6s ease;
	border-radius: 0 3px 3px 0;
	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: rgba(0,0,0,0.8);
}
 
/* Caption text */
.text {
	color: #f2f2f2;
	font-size: 15px;
	padding: 8px 12px;
	position: absolute;
	bottom: 8px;
	width: 100%;
	text-align: center;
}
 
/* Number text (1/3 etc) */
.numbertext {
	color: #f2f2f2;
	font-size: 12px;
	padding: 8px 12px;
	position: absolute;
 	top: 0;
}
 
/* The dots/bullets/indicators */
.dot {
	cursor: pointer;
	height: 15px;
	width: 15px;
	margin: 0 2px;
	background-color: #bbb;
	border-radius: 50%;
	display: inline-block;
	transition: background-color 0.6s ease;
}
 
.active, .dot:hover {
	background: #717171;
}
 
/* Fading animation */
.fade {
	-webkit-animation-name: fade;
	-webkit-animation-duration: 1.5s;
	animation-name: fade;
	animation-duration: 1.5s;
}
 
@-webkit-keyframes fade {
	from {opacity: .4} 
	to {opacity: 1}
}
 
@keyframes fade {
	from {opacity: .4} 
	to {opacity: 1}
}
 
/* On smaller screens, decrease text size */
@media only screen and (max-width: 300px) {
.prev, .next,.text {
	font-size: 11px;
}
}

the HTML code

<div class="slideshow-container">
 
<div class="mySlides fade">
  <div class="numbertext">1 / 3</div>
  <img src="https://codesnippets.littlenerdwebdesign.co.uk/wp-content/uploads/2022/05/example-image.jpg" style="width:100%">
  <div class="text">Caption Text</div>
</div>
 
<div class="mySlides fade">
  <div class="numbertext">2 / 3</div>
  <img src="https://codesnippets.littlenerdwebdesign.co.uk/wp-content/uploads/2022/05/aaa.png" style="width:100%">
  <div class="text">Caption Two</div>
</div>
 
<div class="mySlides fade">
  <div class="numbertext">3 / 3</div>
  <img src="https://codesnippets.littlenerdwebdesign.co.uk/wp-content/uploads/2022/05/cactus.png" style="width:100%">
  <div class="text">Caption Three</div>
</div>
 
<a class="prev" onclick="plusSlides(-1)">&#10094;</a>
<a class="next" onclick="plusSlides(1)">&#10095;</a>
 
</div>
<br>
 
<div style="text-align:center">
  <span class="dot" onclick="currentSlide(1)"></span> 
  <span class="dot" onclick="currentSlide(2)"></span> 
  <span class="dot" onclick="currentSlide(3)"></span> 
</div>

the JavaScript code

var slideIndex = 1;
showSlides(slideIndex);
 
function plusSlides(n) {
  showSlides(slideIndex += n);
}
 
function currentSlide(n) {
  showSlides(slideIndex = n);
}
 
function showSlides(n) {
  var i;
  var slides = document.getElementsByClassName("mySlides");
  var dots = document.getElementsByClassName("dot");
  if (n > slides.length) {slideIndex = 1}    
  if (n < 1) {slideIndex = slides.length}
  for (i = 0; i < slides.length; i++) {
      slides[i].style.display = "none";  
  }
  for (i = 0; i < dots.length; i++) {
      dots[i].className = dots[i].className.replace(" active", "");
  }
  slides[slideIndex-1].style.display = "block";  
  dots[slideIndex-1].className += " active";
}

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