HTML → Markdown は何をしますか？
HTML → Markdown はブラウザ上でデータやファイルを変換するツールで、結果と制限を明確に示します。 検証済みの機能： ATX or Setext headings, Lists, links, emphasis, and fenced code, Local HTML file input, No embedded resource loading.
When should you use this tool?
Use this tool to migrate document content to Markdown. Use HTML Preview to inspect a document and Markdown Preview to review safe rendered Markdown. Keep original HTML when layout or application behavior matters.
使い方
- Paste HTML or open a local .html file up to 2 MiB.
- Choose # Heading or Setext heading style and select Run.
- Review the Markdown text; copy it or download a .md file.
実際の入出力例
Convert a heading and emphasized paragraph
入力
<h1>Hello</h1><p>A <strong>local</strong> tool.</p>出力
# Hello
A **local** tool.Heading structure and strong emphasis become Markdown syntax; the HTML is never inserted into the live page.
一般的なエラーと対処
| 症状 | 原因 | 対処 |
|---|---|---|
| The output does not retain a complex table layout. | Markdown cannot represent every HTML layout, and GFM table conversion is not enabled. | Simplify the table or use JSON Table for structured Markdown tables. |
| Scripts or styles disappear. | Executable and presentation-only elements are excluded. | Use this converter for document content; keep original HTML when interactive behavior matters. |
Supported behavior and limitations
このツール固有の制限： No remote URL fetching, JavaScript execution, GFM table plugin, CSS layout reconstruction, or round-trip fidelity is provided. Image URLs may appear as Markdown text but are not downloaded. Conversion is not a general HTML sanitizer for use elsewhere.
標準と実装の参考資料
- Turndown (opens in a new tab)Defines conversion rules and supported Markdown syntax.
- LinkeDOM (opens in a new tab)Parses HTML as a local JavaScript DOM without a browser document.
HTML → Markdown — FAQ
Is my input uploaded?
No. Processing happens in a browser Worker. Engine files load from this website; tool input, output, and filenames are not sent to a processing API.
Do I need an account or API key?
No account, API key, or backend processing service is needed.
How do I save a result?
Review the result, then use the Copy or Download control available for that output. Modifying input clears stale results.
What are the limits?
No remote URL fetching, JavaScript execution, GFM table plugin, CSS layout reconstruction, or round-trip fidelity is provided. Image URLs may appear as Markdown text but are not downloaded. Conversion is not a general HTML sanitizer for use elsewhere.
更新内容
実質的な更新： HTML → Markdown: Added local processing, explicit size limits, cancellation, worked examples, error explanations, and downloadable results.