HTML Code

<!DOCTYPE html>

<html lang=en>

<head>

  <meta charset=UTF-8>

  <meta name=viewport content="width=device-width,initial-scale=1">

  <title>typemustmatch — mismatch demo</title>

  <style>body{font-family:system-ui,sans-serif;margin:0;padding:1.5rem;background:#f8fafc;color:#334155;line-height:1.7}h1{margin:0 0 .75rem;font-size:1.25rem;color:#0f172a}.box{max-width:32rem;padding:1rem;border:1px solid #fecaca;border-radius:8px;background:#fef2f2}.hint{font-size:.8125rem;color:#64748b;margin-top:.75rem}code{background:#e2e8f0;padding:.1rem .35rem;border-radius:4px}</style>

</head>

<body>

  <h1>Type mismatch blocked</h1>



  <p>This object points at a PDF but declares <code>type="video/mp4"</code> with <code>typemustmatch</code>:</p>



  <object data=/files/honey-bee.pdf type=video/mp4 typemustmatch class=box>

    <p><strong>Fallback shown:</strong> the file is not video/mp4, so the embed is blocked and this message appears instead.</p>

    <p><a href=/files/honey-bee.pdf>Download the PDF</a></p>

  </object>



  <p class=hint>Without <code>typemustmatch</code>, some browsers might still try to load mismatched content. With it, strict matching is enforced.</p>

</body>

</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

HTML typemustmatch Attribute — fallback content