https://ashorthike.com/js/website.js

1layers = document.getElementsByClassName("parallax");
2
3positionLayers = function(e) {
4	var isMobile = window.matchMedia("only screen and (max-width: 930px)").matches;
5	var scrolled = window.pageYOffset;
6	if (isMobile) {
7		scrolled = 0;
8	}
9
10	var layer, speed, top;
11	for (var i = 0; i < layers.length; i++) {
12		layer = layers[i];
13		speed = layer.getAttribute('data-speed');
14		top = layer.getAttribute('data-top');
15		layer.style.top = (top - scrolled * speed) + "px";
16	}
17};
18
19window.addEventListener('scroll', positionLayers);
20window.onload = positionLayers;