<!DOCTYPE html>
<html>
<head>
    <meta name='viewport' content='width=device-width'>
    <style>
        body {
            height: 100vh;
        }

        ul {
            list-style: none;
        }

        li > ul {
            visibility: hidden;
            padding: 0;
        }

        li:hover > ul {
            visibility: visible;
        }
    </style>
    <script>
        const boundingClientRectArray = (selector) => {
            const rect = document.querySelector(selector).getBoundingClientRect();
            return [rect.left, rect.top, rect.width, rect.height];
        };

        addEventListener('mousemove', (event) => webkit.messageHandlers.testHandler.postMessage(event.type));
    </script>
</head>
<body>
    <ul>
        <li>
            <a id='link' href='https://www.apple.com/'>link</a>
            <ul>
                <li><a href='#'>hover menu</a></li>
            </ul>
        </li>
    </ul>
</body>
</html>