Add Searching Tools with Regular Expression Operators in JavaScript

By Andy Harris

Part of the JavaScript & AJAX For Dummies Cheat Sheet

The regular expression mechanism adds extremely powerful searching tools to your programming. Here are some of the most commonly used regular expressions as they are used in JavaScript.

Operator	Description	Sample pattern	matches	Doesn’t match
. (period)	Any single character except newline	.	E	\n
^	Beginning of string	^a	apple	Banana
$	End of string	a$	banana	Apple
[characters]	Any of a list of characters in braces	[abcABC]	A	D
[char range]	Any character in the range	[a-zA-Z]	F	9
\d	Any single numerical digit	\d\d\d-\d\d\d\d	123-4567	The-thing
\b	A word boundary	\bthe\b	the	Theater
+	One or more occurrences of the previous character	\d+	1234	Text
*	Zero or more occurrences of the previous character	[a-zA-Z]d*	B17, g	7
{digit}	Repeat preceding character digit times	\d{3}-\d{4}	123-4567	999-99-9999
{min, max}	Repeat preceding character at least min but not more than max times	.{2,4}	Ca, com, info	watermelon
(pattern segment)	Store results in pattern memory returned with code	^(.).*\1$	gig, wallow	Bobby