<body onload="start()">
<script>

var speechRecognition = null;
function start()
{
    stop();

    speechRecognition = new webkitSpeechRecognition();
    speechRecognition.onerror = (event) => {
        window.webkit.messageHandlers.testHandler.postMessage("Error: " + event.error + " - " +  event.message);
    }
    speechRecognition.onend = (event) => {
        window.webkit.messageHandlers.testHandler.postMessage("End");
    }
    speechRecognition.start();
}

function stop()
{
    if (!speechRecognition)
        return;

    speechRecognition.stop();
    speechRecognition = null;
}

</script>
</body>