Regular Expression Object

Description

Contains a regular expression pattern.

Syntax 1

var regularexpression = /pattern/[switch]

Syntax 2

var regularexpression = new RegExp("pattern",["switch"])

The regular expression object syntax has these parts:

Part	Description
pattern	Required. The regular expression pattern to use. If you use Syntax 1, delimit the pattern by "/" characters. If you use Syntax 2, enclose the pattern in quotation marks.
switch	Optional. Enclose switch in quotation marks if you use Syntax 2. Available switches are: i (ignore case) g (global search for all occurrences of pattern) gi (global search, ignore case)

Remarks

Regular Expression objects store patterns used when searching strings for character combinations. After the Regular Expression object is created, it is either passed to a string method, or a string is passed to one of the regular expression methods. Information about the most recent search performed is stored in the RegExp object.

Use Syntax 1 when you know the search string ahead of time. Use Syntax 2 when the search string is changing frequently, or is unknown, such as strings taken from user input.

The pattern argument is compiled into an internal format before use. For Syntax 1, pattern is compiled as the script is loaded. For Syntax 2, pattern is compiled just before use, or when the compile method is called.