Dynamic Horizontal / Vertical Image Slider Plugin - slideBox not working
http://www.jqueryscript.net/demo/Dynamic-Horizontal-Vertical-Image-Slider-Plugin-slideBox/
<!DOCTYPE html>
<html>
<title>W3.CSS</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="https://www.w3schools.com/w3css/4/w3.css">
<body>
<h2 class="w3-center">Manual Slideshow</h2>
<div class="w3-content w3-display-container">
<img class="mySlides" src="https://community.jcow.net/uploads/userfiles/201707/19_26_gah75.jpg" style="width:100%">
<img class="mySlides" src="https://community.jcow.net/uploads/userfiles/201707/19_26_0zs0l.jpg" style="width:100%">
<img class="mySlides" src="https://community.jcow.net/uploads/userfiles/201707/19_26_kutca.jpg" style="width:100%">
<img class="mySlides" src="img_forest.jpg" style="width:100%">
<button class="w3-button w3-black w3-display-left" onclick="plusDivs(-1)">❮</button>
<button class="w3-button w3-black w3-display-right" onclick="plusDivs(1)">❯</button>
</div>
<script>
var slideIndex = 1;
showDivs(slideIndex);
function plusDivs(n) {
showDivs(slideIndex += n);
}
function showDivs(n) {
var i;
var x = document.getElementsByClassName("mySlides");
if (n > x.length) {slideIndex = 1}
if (n < 1) {slideIndex = x.length}
for (i = 0; i < x.length; i++) {
x[i].style.display = "none";
}
x[slideIndex-1].style.display = "block";
}
</script>
</body>
</html>
