Regex Tester (JavaScript)
Type a pattern and see what it catches.
This is the browser's own JavaScript RegExp engine. Other languages, Java and Python among them, differ in places.
| # | Position | Match | Groups | Named |
|---|
Pattern and text stay in this browser.
How to use
- Type the pattern and tick the flags you want. Matches appear as you type.
- The table gives the position of each match and whatever the groups caught.
- Put something in the replace box to see the text as it would come out.
Examples
Every number in a line
\d+ on "order 1138, seat 42, gate 7" catches 1138, 42 and 7, and the table says where each one starts.
Korean only
[가-힣]+ keeps the Korean and leaves the Latin alone. Percent-encoded text has to be decoded first — %EA%B0%80 is not a Korean character yet. URL Encoder / Decoder
Groups with names
(?<y>\d{4})-(?<m>\d{2})-(?<d>\d{2}) names its captures, and the table shows y, m and d by name instead of by number.
A pattern that would hang the page
(a+)+$ against a long line of a characters never finishes. Here it runs in a separate thread and is cut off after a second.
FAQ
Which regex flavor is this?
Browser JavaScript (ECMAScript) RegExp; other languages differ in places.
Can a bad pattern freeze the page?
Matching runs in a worker and stops automatically after 1 second.
Is my text sent anywhere?
No. All matching runs in your browser.