JSFiddle - React, Tailwind, and code Playground

by graphettion

HTML

<section class="parallax" data-plx-img="http://loremflickr.com/960/720/cat?random=1.jpg">
  <h2>Proper Background Parallax</h2>
  <p>Works on touch devices including iPhone.</p>
</section>
<section class="parallax" data-plx-img="http://loremflickr.com/960/720/cat?random=2.jpg">
  <h2>Proper Background Parallax</h2>
  <p>Works on touch devices including iPhone.</p>
</section>
<section class="parallax" data-plx-img="http://loremflickr.com/960/720/cat?random=3.jpg">
  <h2>Proper Background Parallax</h2>
  <p>Works on touch devices including iPhone.</p>
</section>
<section class="parallax" data-plx-img="http://loremflickr.com/960/720/cat?random=4.jpg">
  <h2>Proper Background Parallax</h2>
  <p>Works on touch devices including iPhone.</p>
</section>
<section class="parallax" data-plx-img="http://loremflickr.com/960/720/cat?random=5.jpg">
  <h2>Proper Background Parallax</h2>
  <p>Works on touch devices including iPhone.</p>
</section>
<section class="parallax" data-plx-img="http://loremflickr.com/960/720/cat?random=6.jpg">
  <h2>Proper Background Parallax</h2>
  <p>Works on touch devices including iPhone.</p>
</section>

CSS

*,
*:before,
*:after {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-kerning: auto;
}

html {
  -webkit-text-size-adjust: 100%;
  background-color: #ffffff;
}

body {
  width: 100%;
  max-width: 100%;
  margin: 0;
  padding: 0;
  position: relative;
  font-size: 1.8em;
  line-height: 1.3;
  font-weight: 400;
  font-family: 'Open Sans', 'Source Sans Pro', Roboto, 'HelveticaNeue-Light', 'Helvetica Neue Light', 'Helvetica Neue', 'Myriad Pro', 'Segoe UI', Myriad, Helvetica, 'Lucida Grande', 'DejaVu Sans Condensed', 'Liberation Sans', 'Nimbus Sans L', Tahoma, Geneva, Arial, sans-serif;
  -webkit-text-size-adjust: 100%;
  background-color: #ffffff;
}


/*--- Parallax ---*/

.parallax {
  display: block;
  position: relative;
  width: 100%;
  max-width: 100%;
  height: 500px;
  padding: 50px 0;
  background: none;
  z-index: 1;
  text-align: center;
  overflow: hidden;
}

.plx-img {
  display: block;
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 125%;
  z-index: -1;
  background-size: cover;
  background-repeat: no-repeat;
  background-position: center;
}

.parallax h2 {
  display: block;
  font-size: 60px;
  line-height: 66px;
  font-weight: 700;
  text-align: center;
  color: #ffffff;
  text-shadow: 0 1px 5px rgba(0, 0, 0, 0.75);
}

.parallax p {
  display: block;
  width: 600px;
  max-width: 100%;
  margin: 0 auto;
  font-size: 24px;
  line-height: 28px;
  font-weight: 400;
  text-align: center;
  color: #ffffff;
  text-shadow: 0 1px 5px rgba(0, 0, 0, 0.75);
}

@media screen and (max-width: 767px) {
  .parallax h2 {
    font-size: 40px;
    line-height: 46px;
  }
  .parallax p {
    font-size: 18px;
    line-height: 22px;
  }
}

JavaScript

function parallaxImages() {
  // Set the scroll for each parallax individually
  var plx = document.getElementsByClassName('parallax');
  for (i = 0; i < plx.length; i++) {
    var height = plx[i].height;
    var img = plx[i].getAttribute('data-plx-img');
    var plxImg = document.createElement("div");
    plxImg.className += " plx-img";
    plxImg.style.height = (height + 50) + 'px';
    plxImg.style.backgroundImage = 'url(' + img + ')';
    plx[i].insertBefore(plxImg, plx[i].firstChild);
  }
}
parallaxImages();

function plxScroll() {
  var scrolled = window.scrollY;
  var win_height_padded = window.innerHeight * 1.25;
  // Set the scroll for each parallax individually
  var plx = document.getElementsByClassName('parallax');
  for (i = 0; i < plx.length; i++) {
    var offsetTop = plx[i].offsetTop;
    var singleScroll = (scrolled - offsetTop) - 50;
    if (scrolled + win_height_padded >= offsetTop) {
      var plxImg = plx[i].getElementsByClassName('plx-img')[0];
      plxImg.style.top = (singleScroll / 5) + "px";
    }
  }
}
window.addEventListener('load', plxScroll);
window.addEventListener('resize', plxScroll);
window.addEventListener('scroll', plxScroll);