regex101: PCRE (Legacy) Match Workspace

Definition Group(?(DEFINE) (?<XHTML> (?&comment)*\s* (?&DOCTYPE) (?&comment)*\s* (?&HTML) (?&comment)*\s* ) # HTML element (?<HTML> <html(?&attrs)?>(?&content)<\/html> ) # Match content (?<content> \s* (?: ((?&tag) | [^<>]+)\s* )* ) # General tag (?<tag> <((?&tagname))(?&attrs)?\s*(?: \/>| >\s*(?&content)\s* <\/\g'-1'> )|(?&comment) ) # Attributes (?<attrs>\s+ # The name (?&keyword) ( \s*=\s* (?: (?&keyword)|(?&string) ) )? (?&attrs)? ) (?<string> "(?:\\.|.)+?"| '(?:\\.|.)+?' ) (?<comment> \s*\s* ) # Match keyword (?<keyword>[^\s\/>"'=]+) # Match tag name (?<tagname>(?!xml)[A-Za-z_][A-Za-z\d_.-]*) # DOCTYPE expression (?<DOCTYPE> <!doctype\s+x?html\s*(public\s*(?&string))?(\s+(?&string))*> ) )

Group XHTML(?<XHTML> (?&comment)*\s* (?&DOCTYPE) (?&comment)*\s* (?&HTML) (?&comment)*\s* )

(?&comment)*calls group comment as a subroutine, repeated any number of times

\s*any whitespace character, repeated any number of times

(?&DOCTYPE)calls group DOCTYPE as a subroutine

(?&comment)*calls group comment as a subroutine, repeated any number of times

\s*any whitespace character, repeated any number of times

(?&HTML)calls group HTML as a subroutine

(?&comment)*calls group comment as a subroutine, repeated any number of times

\s*any whitespace character, repeated any number of times

Comment: HTML element

Group HTML(?<HTML> <html(?&attrs)?>(?&content)<\/html> )

<htmlthe literal text <html (case insensitive)

(?&attrs)?optionally calls group attrs as a subroutine

>the literal > (62₁₀ / 76₈ / 3E₁₆)

(?&content)calls group content as a subroutine

<the literal < (60₁₀ / 74₈ / 3C₁₆)

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

html> the literal text html> (case insensitive)

Comment: Match content

Group content(?<content> \s* (?: ((?&tag) | [^<>]+)\s* )* )

\s*any whitespace character, repeated any number of times

Non-Capturing Group(?: ((?&tag) | [^<>]+)\s* )*

*repeats the group contents below any number of times:

Group 4((?&tag) | [^<>]+)

1st Alternative(?&tag)

(?&tag)calls group tag as a subroutine

2nd Alternative [^<>]+

Negated Character Class[^<>]+

+matches at least one character outside the set below:

<the literal < (60₁₀ / 74₈ / 3C₁₆)

>the literal > (62₁₀ / 76₈ / 3E₁₆)

\s*any whitespace character, repeated any number of times

Comment: General tag

Group tag(?<tag> <((?&tagname))(?&attrs)?\s*(?: \/>| >\s*(?&content)\s* <\/\g'-1'> )|(?&comment) )

1st Alternative <((?&tagname))(?&attrs)?\s*(?: \/>| >\s*(?&content)\s* <\/\g'-1'> )

<the literal text <

Group 6((?&tagname))

(?&tagname)calls group tagname as a subroutine

(?&attrs)?optionally calls group attrs as a subroutine

\s*any whitespace character, repeated any number of times

Non-Capturing Group(?: \/>| >\s*(?&content)\s* <\/\g'-1'> )

1st Alternative \/>

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

>the literal > (62₁₀ / 76₈ / 3E₁₆)

2nd Alternative >\s*(?&content)\s* <\/\g'-1'>

>the literal text >

\s*any whitespace character, repeated any number of times

(?&content)calls group content as a subroutine

\s*any whitespace character, repeated any number of times

<the literal text <

\/the literal / (47₁₀ / 57₈ / 2F₁₆)

\g'-1'calls group 6 as a subroutine

> the literal text >

2nd Alternative(?&comment)

(?&comment)calls group comment as a subroutine

Comment: Attributes

Group attrs(?<attrs>\s+ # The name (?&keyword) ( \s*=\s* (?: (?&keyword)|(?&string) ) )? (?&attrs)? )

\s+any whitespace character, repeated at least once

Comment: The name

(?&keyword)calls group keyword as a subroutine

Group 8( \s*=\s* (?: (?&keyword)|(?&string) ) )?

?repeats the group contents below at most once:

\s*any whitespace character, repeated any number of times

=the literal = (61₁₀ / 75₈ / 3D₁₆)

\s*any whitespace character, repeated any number of times

Non-Capturing Group(?: (?&keyword)|(?&string) )

1st Alternative (?&keyword)

(?&keyword)calls group keyword as a subroutine

2nd Alternative(?&string)

(?&string)calls group string as a subroutine

(?&attrs)?optionally calls group attrs as a subroutine

Group string(?<string> "(?:\\.|.)+?"| '(?:\\.|.)+?' )

1st Alternative "(?:\\.|.)+?"

"the literal text "

Non-Capturing Group(?:\\.|.)+?

+?repeats the group contents below at least once:

1st Alternative\\.

\\the literal \ (92₁₀ / 134₈ / 5C₁₆)

.any character

2nd Alternative.

"the literal " (34₁₀ / 42₈ / 22₁₆)

2nd Alternative '(?:\\.|.)+?'

Group comment(?<comment> \s*\s* )

Comment: Match keyword

Group keyword(?<keyword>[^\s\/>"'=]+)

Comment: Match tag name

Group tagname(?<tagname>(?!xml)[A-Za-z_][A-Za-z\d_.-]*)

Comment: DOCTYPE expression

Group DOCTYPE(?<DOCTYPE> <!doctype\s+x?html\s*(public\s*(?&string))?(\s+(?&string))*> )

^start of string

\s*any whitespace character, repeated any number of times

(?&XHTML)calls group XHTML as a subroutine

\s*any whitespace character, repeated any number of times

$end of string, or before its final line terminator

Global pattern flags

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

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

i modifier: insensitive. Matches without distinguishing uppercase and lowercase letters

s modifier: single line. Allows a dot to match line terminators

Search reference

Regular Expression

(?(DEFINE)
  (?<XHTML>
    (?&comment)*\s*
    (?&DOCTYPE)
    (?&comment)*\s*
    (?&HTML)
    (?&comment)*\s*
  )

  # HTML element
  (?<HTML>
    <html(?&attrs)?>(?&content)<\/html>
  )

  # Match content
  (?<content>
    \s*
    (?:
      ((?&tag) | [^<>]+)\s*
    )*
  )

  # General tag
  (?<tag>
     <((?&tagname))(?&attrs)?\s*(?:
       \/>|
       >\s*(?&content)\s*
       <\/\g'-1'>
     )|(?&comment)
  )

  # Attributes
  (?<attrs>\s+
    # The name
    (?&keyword) (
      \s*=\s*
      (?:
        (?&keyword)|(?&string)
      )
    )?
    (?&attrs)?
  )

  (?<string>
    "(?:\\.|.)+?"|
    '(?:\\.|.)+?'
  )

  (?<comment>
    \s*<!--(.+?)-->\s*
  )

  # Match keyword
  (?<keyword>[^\s\/>"'=]+)
  # Match tag name
  (?<tagname>(?!xml)[A-Za-z_][A-Za-z\d_.-]*)

  # DOCTYPE expression
  (?<DOCTYPE>
     <!doctype\s+x?html\s*(public\s*(?&string))?(\s+(?&string))*>
  )
)

^\s*(?&XHTML)\s*$

New

<!-- test -->
<!DOCTYPE html 
     PUBLIC "-//W3C//DTD XHTML 1.0 Frameset//EN"
     "http://www.w3.org/TR/xhtml1/DTD/xhtml1-frameset.dtd">
  <html goat:style="''inva'lid css I know">textttt<head></head><body><div class="onfoodstamps"><div class="upper">foo<p>ayyy</p>bar</div>baz</div><br/></head></html>