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7.23 Regular Expression Object

The Regular Expression object contains a regular expression pattern.
 

Methods

compile
 
Compiles a regular expression into an internal format.
 
exec
 
Executes a search for a match in a specified string.
 
test
 
Tests whether a pattern exists in a string.
 

Properties

global
 
Indicates whether the global switch (g) has been used.
 
ignoreCase
 
Indicates whether the ignore case switch (i) has been used.
 
lastIndex
 
The index to start the next match.
 
source
 
The text of the regular expression pattern.
 

Syntax 1

var regularexpression = /pattern/[switch]

Syntax 2

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

Arguments

pattern
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 quotes. Required.
switch
Enclose switch in quotes if you use Syntax 2. Available switches are: i (ignore case) g (global search for all occurrences of pattern) gi (global search, ignore case). Optional.

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.
 

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