<html>
<head>
<script>
    function loaded() {
        try {
            window.webkit.messageHandlers.testHandler.postMessage("loaded");
       } catch(e) { }
    }
</script>
</head>
<body onload="loaded()">
    
<div style="width:25px; height:800px;"></div>
<iframe width="320" height="240" src="test.mp4" />

</body>
</html>