Regex for HTML comment
HTML <!-- comment --> block.
The HTML comment regex is <!--[\s\S]*?--> — copy it below, or open it in the explainer for a token-by-token breakdown.
The pattern
<!--[\s\S]*?-->
What it matches
<!-- single line --><!-- multi line --><!---->
What it doesn't match
// not html<!-- unterminated
Notes & gotchas
Lazy quantifier and [\s\S] together match comments spanning multiple lines without needing the /s flag.
Code in your language
Use the explainer's Code tab to generate ready-to-paste snippets in JavaScript, Python, Java, .NET, Go, Ruby, and PHP for this pattern.
Open in explainer →Token-by-token breakdown
Every part of the pattern, left to right:
| Token | Meaning |
|---|---|
<!-- | literal text “<!--” |
[\s\S]*? | zero or more (lazy — as few as possible): any of: whitespace, non-whitespace |
--> | literal text “-->” |
About this pattern
Developer-oriented patterns help with code analysis, log parsing, and data transformation. Use these in build scripts, CI tools, and code review utilities.
Quick usage in different languages
This exact pattern — with the correct escaping and idioms for each language:
- JavaScript:
/<!--[\s\S]*?-->/.test(value) - Python:
re.match(r"<!--[\s\S]*?-->", value) - Java:
Pattern.compile("<!--[\\s\\S]*?-->").matcher(value).matches() - C# / .NET:
Regex.IsMatch(value, @"<!--[\s\S]*?-->") - Go:
regexp.MustCompile(`<!--[\s\S]*?-->`).MatchString(value) - Ruby:
/<!--[\s\S]*?-->/.match?(value) - PHP:
preg_match('~<!--[\s\S]*?-->~', $value)
The explainer’s Code tab regenerates these for any pattern you paste, and the downloadable cheat sheet bundles the breakdown, all seven snippets, and the pitfalls below onto one printable page.
Common pitfalls
- Not anchored. Without ^ and $ this can match a substring anywhere in the input — add anchors if you need the whole value to conform.
- Escape it correctly per language. In Java and JavaScript strings each backslash must be doubled (\\d); in Python, Go, and C# use raw/verbatim strings so the backslashes survive.
- Validate beyond format. Matching the format doesn't guarantee the value is real. Confirm the html comment against a source of truth (database, API, or checksum) where it matters.
Standards & sources
This pattern is based on the following authoritative specification(s) and issuing authorities. Formats can change — always confirm against the primary source.
Related patterns
More patterns in the Developer category:
- HTML tag
- Line comment (// or #)
- Block comment (/* */)
- Docker volume mount
- File path (Unix)
- GitHub issue reference
See also
Browse all 300 patterns in the library, or open this regex in the interactive explainer for a token-by-token breakdown, live testing, and code in seven languages.
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