JSFiddle - React, Tailwind, and code Playground

HTML

<button class="my-button">Toggle BG</button>

CSS

body {
    background-size: cover; 
    background-repeat: no-repeat;  
    background-attachment: fixed;
}
body.active-class {
    background: url('http://wallreborn.com/wp-content/uploads/2015/06/abstract-images-8-Cool-Wallpaper.jpg');
}

JavaScript

jQuery(function($) {
    $('.my-button').click(function() {
        $('body').toggleClass('active-class');
        return false;
    });
});