πŸ” HTML Diff Checker

Updated: 2026-07-11
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How to Use

  1. Paste the original HTML code in the left textarea
  2. Paste the new HTML code in the right textarea
  3. Click "Compare" to analyze differences
  4. View highlighted additions (green), deletions (red), and changes (yellow)

Frequently Asked Questions

Q: How is HTML diff different from plain text diff?

HTML diff is optimized for HTML structure changes. This tool uses LCS (Longest Common Subsequence) algorithm for line-level diff detection, suitable for comparing HTML snippets, templates, and web page structural changes.

Q: How to read the diff results?

Results show side-by-side with line numbers. Green lines (+) = added content, Red lines (-) = removed content, Yellow lines = modified content. Line numbers help locate specific changes.

Q: Is my code secure?

Absolutely. All comparison happens in your browser. Your code is never uploaded to any server. Safe for sensitive code comparison.

Q: Does it support Chinese characters?

Yes. The Unicode-based comparison algorithm handles Chinese, Japanese, Korean, and all multi-byte characters correctly.

Q: Does this tool work offline?

Yes. Once loaded, this tool works entirely in your browser with no network requests. All processing is done client-side.