Usage: Include the CSS and Javascript for Spin.js and Ladda effect: <link rel="stylesheet" href="dist/ladda-themeless.min.css"> <script src="dist/spin.min.js"></script> <script src="dist/ladda.min.js"></script> Then to produce a button with the Ladda effect: <button class="btn btn-primary ladda-button" data-style="expand-left"><span class="ladda-label">expand-left</span></button> Or using "a" tag: