Forked from ohiosveryown/change-class-on-scroll.html
Created
January 29, 2021 12:36
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Vanilla JS – change/add class based on scroll position.
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// https://codepen.io/cmykw/pen/gemxJm | |
// layout | |
<nav/> | |
// style | |
<style> | |
body { min-height: 200vh; } | |
nav { | |
--ease: all 300ms ease; | |
position: fixed; | |
background: pink; | |
height: 72px; | |
width: 100%; | |
opacity: 0.2; | |
transition: var(--ease); | |
} | |
nav.fade-in { opacity: 1; } | |
</style> | |
// logic | |
<script> | |
let scrollpos = window.scrollY | |
const header = document.querySelector("nav") | |
const header_height = header.offsetHeight | |
const add_class_on_scroll = () => header.classList.add("fade-in") | |
const remove_class_on_scroll = () => header.classList.remove("fade-in") | |
window.addEventListener('scroll', function() { | |
scrollpos = window.scrollY; | |
if (scrollpos >= header_height) { add_class_on_scroll() } | |
else { remove_class_on_scroll() } | |
console.log(scrollpos) | |
}) | |
</script> |
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