Regular Expressions 101

Save & Share

Flavor

  • PCRE2 (PHP >=7.3)
  • PCRE (PHP <7.3)
  • ECMAScript (JavaScript)
  • Python
  • Golang
  • Java 8

Function

  • Match
  • Substitution
  • List
  • Unit Tests (7)
/
<(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...

Code Generator

Generated Code

Loading code sample...
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report.
For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php