- JavaScript RegExp Tutorial
- JavaScript RegExp - Home
- JavaScript RegExp - Overview
- Brackets
- JavaScript RegExp - [...]
- JavaScript RegExp - [^...]
- JavaScript RegExp - [0-9]
- JavaScript RegExp - [a-z]
- JavaScript RegExp - [A-Z]
- JavaScript RegExp - [a-zA-Z]
- Quantifiers
- JavaScript RegExp - p+
- JavaScript RegExp - p*
- JavaScript RegExp - p?
- JavaScript RegExp - p{N}
- JavaScript RegExp - p{N1,N2}
- JavaScript RegExp - p{N,}
- JavaScript RegExp - p$
- JavaScript RegExp - ^p
- Matching Characters
- JavaScript RegExp - [^a-zA-Z]
- JavaScript RegExp - p.p
- JavaScript RegExp - ^.{2}$
- JavaScript RegExp - <b>(.*)</b>
- JavaScript RegExp - p(hp)*
- Literal Characters
- JavaScript RegExp - Alphanumeric
- JavaScript RegExp - \0
- JavaScript RegExp - \t
- JavaScript RegExp - \n
- JavaScript RegExp - \v
- JavaScript RegExp - \f
- JavaScript RegExp - \r
- JavaScript RegExp - \xnn
- JavaScript RegExp - \uxxxx
- Meta Characters
- JavaScript RegExp - .
- JavaScript RegExp - \s
- JavaScript RegExp - \S
- JavaScript RegExp - \d
- JavaScript RegExp - \D
- JavaScript RegExp - \w
- JavaScript RegExp - \W
- JavaScript RegExp - [aeiou]
- JavaScript RegExp - [^aeiou]
- JavaScript RegExp - (foo|bar|baz)
- Modifiers
- JavaScript RegExp - i
- JavaScript RegExp - g
- Properties
- JavaScript RegExp - constructor
- JavaScript RegExp - global
- JavaScript RegExp - ignoreCase
- JavaScript RegExp - lastIndex
- JavaScript RegExp - multiline
- JavaScript RegExp - source
- Methods
- JavaScript RegExp - exec()
- JavaScript RegExp - test()
- JavaScript RegExp - toSource()
- JavaScript RegExp - toString()
- JavaScript RegExp Useful Resources
- JavaScript RegExp - Quick Guide
- JavaScript RegExp - Useful Resources
- JavaScript RegExp - Discussion
JavaScript RegExp - lastIndex
Description
lastIndex a read/write property of RegExp objects. For regular expressions with the "g" attribute set, it contains an integer that specifies the character position immediately following the last match found by the RegExp.exec() and RegExp.test() methods. These methods use this property as the starting point for the next search they conduct.
This property allows you to call those methods repeatedly, to loop through all matches in a string and works only if the "g" modifier is set.
This property is read/write, so you can set it at any time to specify where in the target string, the next search should begin. exec() and test() automatically reset the lastIndex to 0 when they fail to find a match (or another match).
Syntax
Its syntax is as follows −
RegExpObject.lastIndex
Return Value
Returns an integer that specifies the character position immediately following the last match.
Example
<html> <head> <title>JavaScript RegExp lastIndex Property</title> </head> <body> <script type = "text/javascript"> var str = "Javascript is an interesting scripting language"; var re = new RegExp( "script", "g" ); re.test(str); document.write("Test 1 - Current Index: " + re.lastIndex); re.test(str); document.write("<br />Test 2 - Current Index: " + re.lastIndex); </script> </body> </html>
Output
Test 1 - Current Index: 10 Test 2 - Current Index: 35