Question 1

How do I use capture groups in the replacement?

Accepted Answer

Use $1, $2, $3 etc. to reference capture groups. For example, replace (\w+)@(\w+) with $1 at $2.

Question 2

What regex flags are supported?

Accepted Answer

Global (g), Case-insensitive (i), Multiline (m), DotAll (s) and Unicode (u). You can combine any flags.

Question 3

Can I use lookbehind and lookahead?

Accepted Answer

Yes. Modern browsers support lookbehind (?<=...) and (?<!...) as well as lookahead (?=...) and (?!...) in regular expressions.

Question 4

Is my text data safe?

Accepted Answer

Yes. All regex matching and replacement happens entirely in your browser. No data is sent to any server.