<!DOCTYPE html>
<html>
<head>
    <style>
        video {
            width: 480px;
            height: 320px;
            position: absolute;
        }

        button {
            top: 320px;
            left: 20px;
            position: absolute;
        }

        body {
            margin: 0;
        }
    </style>
    <script>
        function playing() {
            setTimeout(function() {
                try {
                    window.webkit.messageHandlers.testHandler.postMessage("playing");
                } catch(e) {
                }
            }, 0);
        }

        function mousedown() {
            document.querySelector("video").muted = true;
        }

        function removeVideoElement() {
            document.body.removeChild(document.querySelector("video"));
            return document.querySelector("video");
        }

        function pause() {
            document.querySelector("video").pause();
        }

        function stopped() {
            setTimeout(function() {
               try {
                    window.webkit.messageHandlers.testHandler.postMessage("paused");
               } catch(e) {
                   console.debug(`error: ${e}`);
               }
           }, 0);
        }

    </script>
</head>
<body>
    <video autoplay title="foo" onmousedown=mousedown() onplaying=playing() onpause=stopped()><source src="large-video-with-audio.mp4"></video>
    <button onclick="console.log(removeVideoElement())">Stop!</button>
</body>
<html>