Falling Slider

Slider using random numbers for sliding into and out of place instead of side-to-side.

by Travis Almand

HTML

<div id="container">
  <div id="next"></div>
  <div id="prev"></div>
  <div id="slides_container">
    <img class="slide-base" src="http://lorempixel.com/400/200/abstract/1" />
    <img class="slide" src="http://lorempixel.com/400/200/animals/2" />
    <img class="slide" src="http://lorempixel.com/400/200/business/3" />
    <img class="slide" src="http://lorempixel.com/400/200/cats/4" />
    <img class="slide" src="http://lorempixel.com/400/200/food/5" />
    <img class="slide" src="http://lorempixel.com/400/200/animals/6" />
    <img class="slide" src="http://lorempixel.com/400/200/business/7" />
    <img class="slide" src="http://lorempixel.com/400/200/cats/8" />
    <img class="slide" src="http://lorempixel.com/400/200/food/9" />
    <img class="slide" src="http://lorempixel.com/400/200/animals/10" />
  </div>
</div>

CSS

:root {
  --angle: 45deg;
}

#container {
  border: 1px solid black;
  height: 200px;
  margin: auto;
  position: relative;
  text-align: center;
  width: 400px;
}
#container:hover #next,
#container:hover #prev {
  opacity: 1;
}
#next,
#prev {
  background-color: rgba(255, 255, 255, 0.25);
  cursor: pointer;
  height: 100%;
  left: 0;
  opacity: 0;
  position: absolute;
  top: 0;
  transition: opacity 0.5s;
  width: 30px;
  z-index: 2;
}
#next {
  left: auto;
  right: 0;
}
#next:before,
#prev:before {
  color: white;
  content: '\276D';
  font-size: 40px;
  left: 50%;
  position: absolute;
  top: 50%;
  transform: translate3d(-50%, -50%, 0);
}
#prev:before {
  content: '\276C';
}

#slides_container {
  overflow: hidden;
  position: relative;
}
#slides_container .slide {
  left: 0;
  position: absolute;
  top: 0;
}
#slides_container .next {
  animation: 1.5s fall_out forwards;
}
#slides_container .prev {
  animation: 1s fall_in forwards;
}

@keyframes fall_out {
  from {
    opacity: 1;
    transform: translate3d(0, 0, 0) rotate(0);
  }
  to {
    opacity: 0;
    transform: translate3d(0, 200%, 0) rotate(var(--angle));
  }
}
@keyframes fall_in {
  from {
    opacity: 0;
    transform: translate3d(0, -150%, 0) rotate(var(--angle));
  }
  to {
    opacity: 1;
    transform: translate3d(0, 0, 0) rotate(0);
  }
}

JavaScript

var $next = document.querySelector('#next');
var $prev = document.querySelector('#prev');
var $slidesContainer = document.querySelector('#slides_container');
var $slides = Array.from(document.querySelectorAll('#slides_container .slide'));
var currentSlide = $slides.length - 1;

$next.addEventListener('click', function () {
  if (($slides.length - 1) - document.querySelectorAll('.next').length >= 0) {
		$slides[currentSlide].classList.remove('prev');
		$slides[currentSlide].classList.add('next');
    randVars();
    currentSlide--;
  }
});

$prev.addEventListener('click', function () {
	if (document.querySelectorAll('.prev').length !== $slides.length && document.querySelectorAll('.next').length !== 0) {
		$slides[currentSlide + 1].classList.remove('next');
		$slides[currentSlide + 1].classList.add('prev');
    randVars();
    currentSlide++;
  }
});

function randVars () {
	var minAngle = -90;
  var maxAngle = 90;
	document.documentElement.style.setProperty('--angle', Math.floor(Math.random() * (maxAngle - minAngle + 1)) + minAngle + 'deg');
}