JSFiddle - React, Tailwind, and code Playground

by Michele Marcucci

HTML

<div class="stretcher" id="bg"></div>

CSS

.stretcher {
    position: absolute;
    left: 0px;
    top: 0px;
    z-index: -69;
    width:100%;
    height:100%;
}

JavaScript

function cycle() {
    var header = document.getElementById('bg');
    var pictures = new Array('http://advancement.georgetown.edu/advent/wallpapers/ui/img/1366x768/SealWP_1366x768.jpg', 'http://www.sonymobile.co.jp/xperia/docomo/so-01d/common/download/wallpaper/1366-768/xperiaplaywp_1366-768_bk02.jpg');
    var numPics = pictures.length;
    if (document.images) {
        var chosenPic = Math.floor((Math.random() * numPics));
        header.style.background = 'url(' + pictures[chosenPic] + ')';
        header.style.backgroundSize = 'cover';
    }
}

cycle();