JavaScript Tutorial

Regular exp In JavaScript
Previous Home Next

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);
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


Regular Expression Quantifiers :

Expression Description
* 0 or more
+ 1 or more
? 0 or 1
{2} Exactly 2
{2, 5} Between 2 and 5
{2,} 2 or more

Literal characters :

Character Description
\0 The NUL character (\u0000)
\t Tab (\u0005)
\n Newline (\u000A)
\f Form feed (\u000C)
\r Carriage return (\u000D)
Previous Home Next

Tolal:0 Click:

Show All Comments

Did not find what you were looking for leave your name and message. We will revert within 24 hours
Comment / Feedback: