| ^ | Start of string |
| \A | Start of string |
| $ | End of string |
| \Z | End of string |
| \b | Word boundary |
| \B | Not word boundary |
| \< | Start of word |
| \> | End of word |
|
| \c | Control Character |
| \s | White Space |
| \S | Not white Space |
| \d | Digit |
| \D | Not digit |
| \w | Word |
| \W | Not word |
| \x | Hexadecimal digit |
| \O | Octal digit |
|
| ?= | Lookahead assertion |
| ?! | Negative lookahead |
| ?<= | Lookbehind assertion |
| ?!= or also ? | Negative lookbehind |
| ?> | Once-only Subexpression |
| ?() | Condition [If Then] |
| ?()| | Condition [If Then Else] |
| ?# | Comment |
|
| * | 0 or more occurences |
| + | 1 or more occurences |
| ? | 0 or 1 occurences |
| {5} | Exactly 5 occurences (or any other number instead of 5) |
| {5,} | 5 or more occurences |
| {5,8} | 5, 6, 7 or 8 occurences |
|
| x? | Ungreedy version of "x", where x is a quantifier (see before) |
| Note that all of these characters need to be escaped (see escape character above) |
| ^ | $ | ( | ) | < | > |
| [ | { | \ | | | . | * |
| + | ? |
|
| g | Global match |
| i | Make case-insensitive |
| m | Match multiple lines |
| s | Treat a string as a single line |
| x | Allow the occurence of whitespace and comments in the string |
| e | Evaluate the replacement |
| U | Use an Ungreedy pattern |
|
| \n | Newline |
| \r | Carriage return |
| \t | Tab |
| \v | Vertical tab |
| \f | Form feed |
| \xxx | Octal character xxx |
| \xhh | Hex character hh |
|
| . | Matches all characters except newline |
| (x|y) | Matches x or y |
| (...) | A group, matches the group exactly (xyz) matches 'xyz' |
| (?:...) | Lazy group, matches every occurence of group, not only the first and the last (as greedy does) |
| [xyz] | Range, matches x, y or z |
| [^xyz] | Negative range, matches NOT x, y or z |
| [a-z] | Matches any letter between a and z |
| [A-Z] | Matches any upper case letter between a and z |
| [0-9] | Matches any number between 0 and 9 (digit) |
| \x | Matches the "x"-th occurence of the pattern |
|
| $x | Replaces "x"-th non-passive group that matches |
| $2 | Replaces "def" in /^(abc(def))$/ |
| $1 | Replaces "def" in /^(?:abc(def))$/ |
| $` | Replaces before the matched string |
| $' | Replaces after the matched string |
| $+ | Replaces the last matched string |
| $& | Replaces the entire matched string |
|