title: Firefox - ReferenceError: PaymentRequest is not defined
body: <p>I am trying to implement google pay on a website. The external library for google pay is loaded from pay.google.com. In this google script, they call the browser api PaymentRequest(). This api is built in popular browsers like Safari, Chrome, etc.</p>
  <p>I have google pay working, but it does not work on Firefox. When the external script is loaded, it calls PaymentRequest and in the console the following error is shown:
  ReferenceError: PaymentRequest is not defined</p>
  <p>Link to google pay script
  <a href="https://pay.google.com/gp/p/js/pay.js" rel="noreferrer">https://pay.google.com/gp/p/js/pay.js</a></p>
  <p>Mozilla Firefox official webpage states that PaymentRequest is supported in secure context.
  <a href="https://developer.mozilla.org/en-US/docs/Web/API/Payment_Request_API/Using_the_Payment_Request_API" rel="noreferrer">https://developer.mozilla.org/en-US/docs/Web/API/Payment_Request_API/Using_the_Payment_Request_API</a></p>
  <p>I copy and paste only the same code provided from the official source
  <a href="https://i.stack.imgur.com/bbh0Y.png" rel="noreferrer"><img src="https://i.stack.imgur.com/bbh0Y.png" alt="enter image description here" /></a></p>
  <p>From my perspective, PaymentRequest is not supported in Firefox and does not work. What am I missing?</p>
  <p>Check out the console for both chrome and safari.
  <a href="https://i.stack.imgur.com/zWlOZ.png" rel="noreferrer"><img src="https://i.stack.imgur.com/zWlOZ.png" alt="enter image description here" /></a></p>