<!-- html fragment -->
<div id="container"></div>

// javascript fragment
const container = document.getElementById('container');
const button = googlePayClient.createButton({
  buttonColor: 'default',
  buttonType: 'buy',
  buttonRadius: 4,
  onClick: () => {},
  allowedPaymentMethods: [] // use the same payment methods as for the loadPaymentData() API call
});

container.appendChild(button);