Scroll vanilla js

by ddrraaggaa

HTML

<div id="myID" class="bottomMenu hide"></div>

CSS

body {
    height: 2000px;
}
.bottomMenu {
    position: fixed;
    bottom: 0;
    width: 100%;
    height: 60px;
    border-top: 1px solid #000;
    background: red;
    z-index: 1;
    transition: all 1s;
}
.hide {
    opacity:0;
    left:-100%;
}
.show {
    opacity:1;
    left:0;
}

JavaScript

myID = document.getElementById("myID");

var myScrollFunc = function () {
    var y = window.scrollY;
    if (y >= 20) {
        myID.className = "bottomMenu show"
    } else {
        myID.className = "bottomMenu hide"
    }
};

window.addEventListener("scroll", myScrollFunc);