🔎 正则表达式测试Regexp Tester
在文本上测试 JavaScript 正则：列出全部匹配（位置与分组）或执行替换，边输入边更新；过慢的模式会被自动中止，页面不会卡死。本地处理。Test a JavaScript regular expression on text: list every match (position and groups) or run a replace, updating as you type; a pattern that runs too long is stopped so the page never freezes. Processed locally.
使用说明与常见问题How-to & FAQ
「正则表达式测试」是什么？What is the Regexp Tester tool?
在文本上测试 JavaScript 正则：列出全部匹配（位置与分组）或执行替换，边输入边更新；过慢的模式会被自动中止，页面不会卡死。本地处理。Test a JavaScript regular expression on text: list every match (position and groups) or run a replace, updating as you type; a pattern that runs too long is stopped so the page never freezes. Processed locally.
如何使用「正则表达式测试」？How do I use the Regexp Tester tool?
在「正则表达式测试」中，按需设置「正则」、「标志」、「替换为（可选）」等选项，然后点击「运行」按钮即可。In the Regexp Tester: Set "Pattern", "Flags", "Replace with (optional)", then click "Run".
会上传吗？Is anything uploaded?
不会。正则在浏览器本地的后台线程（Web Worker）里运行。No. The regular expression runs locally in a background thread (Web Worker) in your browser.
为什么提示“灾难性回溯”？Why does it say "catastrophic backtracking"?
有些模式（如 (a+)+$、(x|x)*y）在不匹配时要尝试的组合会指数级增长。本页在后台线程中运行匹配，超过 1.5 秒就中止并提示，页面不会卡死；请改写嵌套量词或加锚点。Some patterns (such as (a+)+$ or (x|x)*y) try an exponential number of combinations when they fail. Matching runs in a background thread and is stopped after 1.5 s with this message, so the page never freezes; rewrite the nested quantifiers or add anchors.
会自动重新运行吗？Does it re-run automatically?
会。修改模式、标志、文本或替换内容后约 0.3 秒自动重新运行；也可以按回车或点“运行”。Yes. It re-runs about 0.3 s after you change the pattern, flags, text or replacement; you can also press Enter or click Run.
结果里的 @ 数字是什么？What is the @ number in the results?
匹配在文本中的起始位置（从 0 开始，按 UTF-16 码元计数，与 JavaScript 的 index 一致），后面列出捕获分组和命名分组。The match's start position in the text (from 0, counted in UTF-16 code units, the same as JavaScript's index), followed by the capture groups and named groups.
有哪些选项可以调整？What options can I adjust?
「正则表达式测试」的设置：「正则」默认 \w+；「标志」默认 g；「替换为（可选）」可留空。每次生成结果都按当前设置处理。Settings in the Regexp Tester — "Pattern" default \w+; "Flags" default g; "Replace with (optional)" optional. The result always uses the current settings.
「正则表达式测试」免费吗？需要注册吗？Is the Regexp Tester free? Do I need an account?
「正则表达式测试」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Regexp Tester is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.