Tools/TestWebKitAPI/Resources/simple-nested-model-page.html

<iframe>
<model stagemode='orbit'>
    <source src='cube.usdz'>
</model>
</iframe>
<script>
    document.querySelector('model').addEventListener('load', event => window.webkit.messageHandlers.modelLoading.postMessage('LOADED'));
    document.querySelector('model').ready.then((result) => window.webkit.messageHandlers.modelLoading.postMessage('READY'));
</script>