LayoutTests/editing/async-clipboard/resources/sanitize-when-reading-markup-iframe.html

<button id='copy' style='font-size: 40px; text-align: center;'>Click to copy</button>
<script>
    const markup1 = `<script>console.log('This script tag should be sanitized out.')</${'script'}><p onclick='javascript:void()'>Hello world 1</p>`;
    const markup2 = `<p style='display: none;'>You should not see this text.</p><span>Hello world 2</span>`;
    copy.addEventListener('click', async () => {
        await navigator.clipboard.write([
            new ClipboardItem({ 'text/html' : markup1 }),
            new ClipboardItem({ 'text/html' : markup2 })
        ]);
        parent.postMessage('finished-copying', '*');
    });
</script>