<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Security-Policy" content="script-src 'nonce-b'">
</head>
<body>
<script>
</script>
<script nonce="b">
    document.addEventListener('securitypolicyviolation', e => {
        window.webkit.messageHandlers.testHandler.postMessage("document-uri: " + e.documentURI);
    });
</script>
</body>
</html>