Regular Expressions 101

1st Alternative(?:^&[^&;]*?)?(39)(?!(?:[^&;]*?;))

Non-Capturing Group(?:^&[^&;]*?)?

?repeats the group contents below at most once:

^start of line

&the literal & (38₁₀ / 46₈ / 26₁₆)

Negated Character Class[^&;]*?

*?matches any number of characters outside the set below:

&the literal & (38₁₀ / 46₈ / 26₁₆)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

Group 1(39)

39the literal text 39

Negative Lookahead(?!(?:[^&;]*?;))

Non-Capturing Group(?:[^&;]*?;)

Negated Character Class[^&;]*?

*?matches any number of characters outside the set below:

&the literal & (38₁₀ / 46₈ / 26₁₆)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

2nd Alternative(?:(?:^|;)(?:[^&;]*?)(39))

Non-Capturing Group(?:(?:^|;)(?:[^&;]*?)(39))

Non-Capturing Group(?:^|;)

1st Alternative^

^start of line

2nd Alternative;

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

Non-Capturing Group(?:[^&;]*?)

Negated Character Class[^&;]*?

*?matches any number of characters outside the set below:

&the literal & (38₁₀ / 46₈ / 26₁₆)

;the literal ; (59₁₀ / 73₈ / 3B₁₆)

Group 2(39)

39the literal text 39

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?:^&[^&;]*?)?(39)(?!(?:[^&;]*?;))|(?:(?:^|;)(?:[^&;]*?)(39))

New

39;&39&lt;img border=39&#039;0&#039;&39; &39 &39; 39test; 39; /&gt;39
39; 39%; some text in between without searched text; 39 test &; test39 39 23 39; test test 39
&&&39 ;;39 &; 39;
padding: 39%;

Regular Expression

Extraction