<html>
<head>
<style>
    body {
        padding: 0;
        margin: 0;
        widows: 100%;
        height: 100%;
    }

    img {
        width: 100%;
    }
</style>
<script>
    var messageChannel = '{{message_channel}}';
    window.onload = function() {
        var img = document.getElementById('screen');
        if (img) {
            window[messageChannel].postMessage(document.body.clientWidth / img.offsetHeight);
        }
    };
</script>
</head>
<body>
<img id="screen" src="{{stream_url}}">
</body>
</html>