Regular Expressions 101

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/
<(script|style)((?:(?!src|nonce).)*?)>
/
gm
< matches the character < with index 6010 (3C16 or 748) literally (case sensitive)
1st Capturing Group
(script|style)
1st Alternative
script
script
matches the characters script literally (case sensitive)
2nd Alternative
style
style
matches the characters style literally (case sensitive)
2nd Capturing Group
((?:(?!src|nonce).)*?)
Non-capturing group
(?:(?!src|nonce).)*?
*? matches the previous token between zero and unlimited times, as few times as possible, expanding as needed (lazy)
Negative Lookahead
(?!src|nonce)
Assert that the Regex below does not match
1st Alternative
src
src
matches the characters src literally (case sensitive)
2nd Alternative
nonce
nonce
matches the characters nonce literally (case sensitive)
. matches any character (except for line terminators)
> matches the character > with index 6210 (3E16 or 768) literally (case sensitive)
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gm

Test String

Substitution

Processing...

Regex Debugger

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