Availability

JavaScript 1.2; JScript 3.0; ECMAScript v3

Literal Syntax

/pattern/attributes

Constructor

new RegExp(pattern, attributes)

Arguments

pattern

A string that specifies the pattern of the regular expression, or another regular expression.

attributes

An optional string containing any of the "g", "i", and "m" attributes that specify global, case-insensitive, and multiline matches. The "m" attribute is not available prior to ECMAScript standardization. If the pattern argument is a regular expression instead of a string, this argument must be omitted.

Returns

A new RegExp object, with the specified pattern and flags. If the pattern argument is a regular expression rather than a string, the RegExp( ) constructor creates a new RegExp object using the same pattern and flags as the specified RegExp. If RegExp( ) is called as a function without the new operator, it behaves just as it would with the new operator, except when pattern is a regular expression; in that case, it simply returns pattern instead of creating a new RegExp object.

Throws

SyntaxError

If pattern is not a legal regular expression or if attributes contains characters other than "g", "i", and "m".

TypeError

If pattern is a RegExp object and the attributes argument is not omitted.

Instance Properties

global

Whether the RegExp has the g attribute.

ignoreCase

Whether the RegExp has the i attribute.

lastIndex

The character position of the last match; used for finding multiple matches in a string.

multiline

Whether the RegExp has the m attribute.

source

The source text of the regular expression.

Methods

exec( )

Performs powerful, general-purpose pattern matching.

test( )

Tests whether a string contains a pattern.

Description

The RegExp object represents a regular expression, a powerful tool for performing pattern matching on strings. See Chapter 10 for complete details on regular expression syntax and use.

See Also

Chapter 10