Regex Tester可以处理什么？
Regex Tester 用于在浏览器中检查数据，并清楚显示处理结果和限制。 已核对的功能： JavaScript RegExp engine, Capture groups, 300 ms worker timeout, 1,000-match cap.
Test against the deployment engine
Use this page for JavaScript patterns. Verify a PCRE, Python, .NET, Java, database, or proxy pattern in that exact engine before deployment.
如何使用？
- Enter the pattern without surrounding slash characters.
- Choose JavaScript flags and paste representative test text.
- Inspect highlighted matches, indexes, and capture groups.
实际输入输出示例
Capture a named numeric identifier
输入
Pattern: order-(?<id>\d+)
Text: order-1042输出
Match: order-1042
Named group id: 1042The browser exposes the full match and the named capture from the JavaScript RegExp result.
常见错误与修复方法
| 现象 | 可能原因 | 修复方法 |
|---|---|---|
| A valid-looking pattern is rejected. | It uses syntax from another regex engine or an unsupported browser flag. | Rewrite the expression for the target JavaScript runtime. |
| Testing times out. | The expression backtracks heavily on the supplied text. | Make repetitions more specific, reduce ambiguity, or use a parser. |
A timeout indicates expensive matching
该工具的实际边界： Nested quantifiers and ambiguous repeated groups can cause excessive backtracking. A 300 ms timeout protects the page but does not certify production safety.
标准与实现参考
- MDN — RegExp (opens in a new tab)Documents JavaScript pattern syntax, flags, and match behavior.
关于Regex Tester的常见问题
Which regex engine is used?
The page uses JavaScript RegExp; PCRE, Python, .NET, and Java can behave differently.
Are capture groups shown?
Yes. Numbered captures and named groups are shown for displayed matches.
What does the timeout mean?
The worker is stopped after 300 ms to reduce page freezes; this is not proof that a pattern is safe.
更新记录
本次实质更新： Regex Tester: Added JavaScript flag validation, highlighted matches, capture groups, a 1,000-match cap, and 300 ms worker termination for slow patterns.