<!-- Loads <model-viewer> for modern browsers: -->
<script type="module"
    src="https://unpkg.com/@google/model-viewer/dist/model-viewer.js">
</script>

<!-- Loads <model-viewer> for old browsers like IE11: -->
<script nomodule
    src="https://unpkg.com/@google/model-viewer/dist/model-viewer-legacy.js">
</script>