Metacharacters (must be escaped)
^
$
(
)
<
.
*
+
?
[
{
\
|
>
Escape Character
\Escape Character
Quantifiers
*
+
?
{3}
{3,}
{3,5}
0 or more
1 or more
0 or 1
Exactly 3
3 or more
3, 4 or 5
Quantifier Modifiers
"x" below represents a quantifier
x?
Ungreedy version of "x"
Anchors
^
\A
$
\Z
\b
\B
\<
\>
Start of string
Start of string
End of string
End of string
Word boundary
Not word boundary
Start of word
End of word
POSIX
[:upper:]
[:lower:]
[:alpha:]
[:alnum:]
[:digit:]
[:xdigit:]
[:punct:]
[:blank:]
[:space:]
[:cntrl:]
[:graph:]
[:print:]
[:word:]
Upper case letters
Lower case letters
All letters
Digits and letters
Digits
Hexadecimal digits
Punctuation
Space and tab
Blank characters
Control characters
Printed characters
Printed characters and
spaces
Digits, letters and
underscore
Character Classes
\c
\s
\S
\d
\D
\w
\W
\x
\O
Control character
White space
Not white space
Digit
Not digit
Word
Not word
Hexadecimal digit
Octal digit
Special Characters
\n
\r
\t
\v
\f
\xxx
\xhh
New line
Carriage return
Tab
Vertical tab
Form feed
Octal character xxx
Hex character hh
Pattern Modifiers
g
i
m
s
x
e
U
Global match
Case-insensitive
Multiple lines
Treat string as single line
Allow comments and
white space in pattern
Evaluate replacement
Ungreedy pattern
Available free from
AddedBytes.com
Assertions
?=
?!
?<=
?!= or ?<!
?>
?()
?()|
?#
Lookahead assertion
Negative lookahead
Lookbehind assertion
Negative lookbehind
Once-only Subexpression
Condition [if then]
Condition [if then else]
Comment
String Replacement (Backreferences)
$n
$2
$1
$`
$'
$+
$&
nth non-passive group
"xyz" in /^(abc(xyz))$/
"xyz" in /^(?:abc)(xyz)$/
Before matched string
After matched string
Last matched string
Entire matched string
Groups and Ranges
.
(a|b)
(...)
(?:...)
[abc]
[^abc]
[a-q]
[A-Q]
[0-7]
\n
Note: Ranges are inclusive.
Any character except
new line (\n)
a or b
Group
Passive Group
Range (a or b or c)
Not a or b or c
Letter between a and q
Upper case letter
between A and Q
Digit between 0 and 7
nth group/subpattern
Sample Patterns
Pattern
([A-Za-z0-9-]+)
(\d{1,2}\/\d{1,2}\/\d{4})
([^\s]+(?=\.(jpg|gif|png))\.\2)
(^[1-9]{1}$|^[1-4]{1}[0-9]{1}$|^50$)
(#?([A-Fa-f0-9]){3}(([A-Fa-f0-9]){3})?)
((?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,15})
(\w+@[a-zA-Z_]+?\.[a-zA-Z]{2,6})
(\<(/?[^\>]+)\>)
Note: These patterns are intended for reference purposes and have not been
extensively tested. Please use with caution and test thoroughly before use.
Will Match
Letters, numbers and hyphens
Date (e.g. 21/3/2006)
jpg, gif or png image
Any number from 1 to 50 inclusive
Valid hexadecimal colour code
String with at least one upper case
letter, one lower case letter, and one
digit (useful for passwords).
Email addresses
HTML Tags