Elegant Scroll to Top - Back to top JavaScript plugin example – Stacking: z-index

You can check out the code below to set the parameters.
Stacking: z-index
Example code
<link rel="stylesheet" href="http://your-domain.com/elegant-scroll-to-top/css/elegant-scroll-to-top.min.css">
<script src="http://your-domain.com/elegant-scroll-to-top/js/elegant-scroll-to-top.min.js"></script>
document.addEventListener('DOMContentLoaded', function() {
    var elegantScrollToTop = new ElegantScrollToTop({        
        zIndex: 1000000000
Related options
Peoprty Possible Values Default Value Description
zIndex e.g. null, 1000, 1111111111, etc. 1000 The z-index of the button.