You can use CDN to include the JS SDK on your website.
<!-- include the default style. -->
<link href="https://sdk.runstellar.com/26.1.3/default.css" rel="stylesheet" type="text/css">
<!-- include the js sdk. -->
<script type="text/javascript" src="https://sdk.runstellar.com/26.1.3/sdk.js" ></script>