<!DOCTYPE html>
<html>
<head>
    <script>

    function pageLoaded() {
        try {
            window.webkit.messageHandlers.testHandler.postMessage('loaded');
        } catch(e) { }
    }

    function playVideo(identifier) {
        document.getElementById(identifier).play().catch(function() {
            try {
                window.webkit.messageHandlers.testHandler.postMessage("did-not-play-" + identifier);
            } catch(e) { }
        });
    }

    function didPlayVideo(identifier) {
        try {
            window.webkit.messageHandlers.testHandler.postMessage("did-play-" + identifier);
        } catch(e) { }
    }

   </script>
</head>
<body onload="pageLoaded()">
    <button onclick="playVideo('video1')">Play Video 1</button>
    <br />
    <video id="video1" onplaying="didPlayVideo('video1')" src="video-with-audio.mp4"></video>
    <video id="video2" onplaying="didPlayVideo('video2')" src="video-with-audio.mp4"></video>
</body>
</html>