HTML Formatter and Minifier は何をしますか？
HTML Formatter and Minifier はブラウザ上でデータを整形・検証するツールで、結果と制限を明確に示します。 検証済みの機能： Prettier HTML formatting, Conservative HTML minification, Inline code left unchanged, Local HTML download.
Format, minify, and sanitize are different jobs
Use formatting for maintenance and review. Use minification only for a tested delivery artifact. Use a dedicated sanitizer when markup comes from an untrusted source; neither formatting nor minification makes HTML safe to render.
使い方
- Choose Format HTML for readable markup or Minify HTML for a compact delivery copy.
- Paste an HTML document or fragment no larger than 2 MB into Input and select Convert.
- Review the output, especially whitespace-sensitive text and embedded code, then copy it or download html-output.html.
実際の入出力例
Format and minify a compact document fragment
入力
<main><h1>KitLumi</h1><!-- remove --><p>Local tools</p></main>出力
<main>
<h1>KitLumi</h1>
<!-- remove -->
<p>Local tools</p>
</main>
Minified: <main><h1>KitLumi</h1><p>Local tools</p></main>Format mode preserves the comment and lays out the markup. Minify mode removes the comment and collapses optional whitespace while retaining explicit tags and quoted attributes.
一般的なエラーと対処
| 症状 | 原因 | 対処 |
|---|---|---|
| The formatted structure is not the structure you expected. | HTML parsing is error-tolerant, so a missing closing tag or invalid nesting can be repaired according to HTML parsing rules. | Correct incomplete or misnested markup before treating the formatted result as an authoritative source. |
| The minified page behaves or renders differently. | Whitespace can be significant in inline content, preformatted text, templates, or code that reads exact text nodes. | Regression-test the output in its real template and browser context; keep the formatted source when whitespace semantics are uncertain. |
| Dangerous markup is still present after minification. | A minifier reduces source size; it does not sanitize scripts, event handlers, URLs, or embedded content. | Use a dedicated allowlist-based HTML sanitizer before rendering any untrusted HTML. |
Important behavior of HTML Formatter
このツール固有の制限： Minification is not sanitization: scripts, event handlers, unsafe URLs, and other active content remain in the output and must still be treated as untrusted.
標準と実装の参考資料
- Prettier browser documentation (opens in a new tab)Documents the standalone browser formatter and explicit HTML parser plugin used by Format HTML.
- html-minifier-terser official repository (opens in a new tab)Documents the HTML minification options and browser distributions used by Minify HTML.
- WHATWG HTML Standard (opens in a new tab)Defines HTML parsing, document structure, and whitespace behavior.
HTML Formatter — FAQ
Does the HTML Formatter upload my input?
No. Processing runs in the current browser tab, and the page does not send tool input to a KitLumi processing endpoint.
What input does the HTML Formatter accept?
It accepts one HTML document or fragment up to 2 MB. The workspace checks the input and reports malformed or unsupported values before it produces a result.
What does the HTML Formatter produce?
It produces Prettier-formatted HTML or conservatively minified HTML. Copy and download controls appear when the output format supports them.
What limitation should I know?
Minification is not sanitization: scripts, event handlers, unsafe URLs, and other active content remain in the output and must still be treated as untrusted.
更新内容
実質的な更新： HTML Formatter: Added Prettier HTML formatting, Conservative HTML minification, Inline code left unchanged, Local HTML download, responsive controls, explicit runtime disclosure, and task-specific examples and limitations.