Test a JavaScript regular expression against pasted text and list the first matches with their positions.
The pattern is compiled as a JavaScript regular expression. Flags may be g, i, m, s, u, or y. The result lists up to 30 matches and the index where each one starts.
The page uses the JavaScript regular-expression language. A pattern that does not compile is rejected with that fact, not with a guessed correction.
Patterns that nest open-ended quantifiers, or that are longer than 80 characters, are refused. A match that runs too long is stopped. This is a tester for ordinary patterns, not a place to explore catastrophic backtracking.
Enter the pattern without surrounding slashes.
Add flags only if you need them. Leave the box empty for a global search.
Paste the text and read the index in front of each match.
The first match is the two a’s at the start, and a later single a matches too.
Wrapping the pattern in /slashes/ and then wondering why the slashes are matched literally.
No. Type the pattern only. Put flags in the flags box.
Nested quantifiers such as (a+)+ can stall a matcher. Rewrite the pattern so the repetition is not nested that way.