index.html

<!doctype html>
<html>

<head>
    <title>Popup Demo</title>
    <!-- <link rel="stylesheet" href="/css/aftermarket.css"> -->
</head>

<body>


    <script type="module">
        import 'https://web3.chainparency.com/components/after-market-popup.js'
    </script>

    <div>
        <button id="popup-button" type="button" onclick="function pop(e) { console.log('pop clicked'); document.querySelector('#popup').show(); }; pop(); return false;">View Certificate</button>
        <after-market-popup id="popup" orgID="aHtm782bf4B1so7sCXuj" amID="EMqsuSZXXfsPiPwS0QfL"></after-market-popup>
    </div>

    <script>
        // This way works and the inline way above works
        document.querySelector("#popup-button").addEventListener("click", () => {
            console.log('click2')
            // let pop = document.querySelector("#popup")
            // pop.show()
        })
    </script>
</body>

</html>