JavaScript Tutorial

javascript also provide Regular expressions that is very powerful tools for performing pattern matches.that is also used in PERL programmers and UNIX shell programmers .

An regular expression is written in the form of pattern or modifiers where pattern is the regular expression itself and modifiers are a series of characters indicating various options. The "modifiers" part is optional.

There are characters which have special use in regular exps : [ \ ^ $ . | ? * + ( ).

There are Manely two methods for creating a RegExp object.

RegExp Literal
RegExp Object Constructor

Syntax :

var pattern = new RegExp(pattern, modifiers);
                             OR
var pattern = /pattern/modifiers;

Brackets are used to find a range of characters :

Expression	Description
[a-z]	It matches any character from lowercase a through lowercase z.
[abc]	Find any character between the brackets
[A-Z]	It matches any character from uppercase A through uppercase Z.
[^abc]	Find any character NOT between the brackets
(x\|y)	Find any of the alternatives specified
[0-9]	It matches any decimal digit from 0 through 9.

Modifiers used in reg() :

Modifier	Meaning	Description
i	Ignore Case	its Perform a case-insensitive matching
g	Global Search	its Perform a global match that's find all matches rather than stopping after the first match.
m	Multiline Input	its Perform a multiline matching