JavaScript Regular Expressions

Pre-defined Classes

Character
Equivalence class
Meaning

.
[^\n\r]
All characters except carriage return and line break

\d
[0-9]
numeric characters

\d
[^0-9]
Non-numeric characters

\s
[\t\n\x0b\f\r]
whitespace characters

\s
[^ \t\n\x0b\f\r]
Non-whitespace characters

\w
[A-za-z_0-9]
Word characters (Letters, numbers, underscores)

\w
[^a-za-z_0-9]
Non-word characters

Boundary

Regular expressions also provide several commonly used boundary-matching characters

Character

Meaning

^

Start with XX

$

End With XX

\b

Word boundaries, meaning characters other than [a-za-z_0-9]

\b

Non-word boundary

Quantifiers

Character
Meaning

?
Occurs 0 or more times (up to one time)

+
One or more occurrences (at least once)

*
Occurs 0 or more times (any time)

N
Appears n times

{N,m}
Occurs N to M times

{N,}
appears at least n times

JavaScript Regular Expressions