JavaScript Regular Expressions

Note: in regular expressions, many punctuation marks have a special meaning. They are:

^ $ . * + ? = ! : | \ / ( ) [ ] { }

Direct-volume characters for regular expressions

character	Match
Alpha-Numeric characters	Their own
/	Nul character (\u0000)
\ t	tab (\u0009)
\ n	Line Break (\u000a)
\v	Vertical tab (\U000B)
\f	Page Break (\u000c)
\ r	Enter (\u000d)
\xnn	The Latin character specified by the hexadecimal number NN, for example, \x0a equivalent to \ n
\uxxxx	The Unicode character specified by the hexadecimal XXXX, for example, \u0009 equivalent to \ t
\cx	Controls the character ^x. For example, \CJ is equivalent to line break \ n

Character classes for regular expressions

character	Match
[...]	Any character that is within the parentheses
[^...]	Any character that is not in parentheses
.	Any character except newline characters and other Unicode line terminators
\w	Any ASCII single character, equivalent to [a-za-z0-9_]
\w	Any non-ASCII single character, equivalent to [^a-za-z0-9_]
\s	Any Unicode Blank Spaces tab page break
\s	Any non-Unicode whitespace characters, note that \w and \s are different
\d	Any ASCII number, equivalent to [0-9_]
\d	Any character other than an ASCII number, equivalent to [^0-9_]
[\b]	Backspace Direct Volume (special case)

Repeating characters for regular expressions

character	meaning
{N,m}	Match the previous item at least n times, but not more than m times
{N,}	Match the previous item n times, or more
N	Match the previous item exactly n times
?	Matches the previous item 0 or 1 times, which means the previous item is optional. Equivalent to {0,1}
+	Matches the previous item 1 or more times, equivalent to {1,}
*	Matches the previous item 0 or more times, equivalent to {0,}

Selection, grouping, and referencing characters of regular expressions

character	meaning
|	Choose. Matches the subexpression to the left of the symbol or to the right sub-expression
(...)	Combination. Combine several items into a single unit, which can be used by symbols such as *, +,?, and |, and you can also remember the characters that match this combination for subsequent reference use
(?:...)	Combination only. Combine items into a single unit, but do not remember characters that match that group
\ n	Matches the first character of the nth grouping. Groups are sub-expressions (possibly nested) in parentheses. The group number is the left-to-right count of the number of open parentheses, grouped by (?: Form does not encode

The anchor character of the regular expression

character	meaning
^	Matches the beginning of a string, in a multi-row search, matches the beginning of a line
$	Matches the end of a string, in a multi-row search, matches the end of a line
\b	Match the boundaries of a word. In short, it is the position between the character \w and \w, or the position between the character \w and the beginning or end of the string (but note that [\b] matches backspace)
\b	Match the position of the non-word boundary
(? =p)	Forward declaration, which requires the next characters to match the pattern p, but does not include those characters in the match
(?! =P)	Anti-forward declaration, requiring the next character not to match the pattern p

Flags for regular expressions

character	meaning
I	Perform a case-insensitive match
G	Performs a global match. In short, find all matches instead of stopping after finding the first one
M	Multiline mode, ^ matches the beginning of a line or the beginning of a string, matches the end of a line or the end of a string

JavaScript Regular Expressions