<script>
   var options = {
       access_token: 'ACCESS_TOKEN', //TODO use access token, received on previous step
       sandbox: true //TODO please do not forget to remove this setting when going live
   };
   var s = document.createElement('script');
   s.type = "text/javascript";
   s.async = true;
   s.src = "https://static.xsolla.com/embed/paystation/1.0.7/widget.min.js";
   s.addEventListener('load', function (e) {
       XPayStationWidget.init(options);
   }, false);
   var head = document.getElementsByTagName('head')[0];
   head.appendChild(s);
</script>

<button data-xpaystation-widget-open>Buy Credits</button>