Tracking a user's IP address through a hidden form field

The script will make a call to an api that returns the clients IP address and then sets the hidden form field to the returned value.

<!DOCTYPE html>
<html>
  <head>
    ...
  </head>
  <body>
    <form name="contact"  action="/form_submission_page.html">
      <input type="text" id="ipFormInput" hidden>
      <input type="submit" value="Send">
    </form>
  </body>

  <script type="application/javascript ">
    const ipFormInput = document.getElementById('ipFormInput');

    fetch('https://api.ipify.org?format=json')
        .then((response) => { return response.json() })
        .then((json) => {
            const ip = json.ip;
            ipFormInput.value = ip;
            console.log(ip);
        })
        .catch((err) => { console.error(`Error getting IP Address: ${err}`) })
  </script>
</html>