lastIndexOf()  String  instance method JS Home  <<  JS Reference  <<  String  <<  lastIndexOf()

Description

Returns the index value for the last occurence of the specified string from the specified starting index.

  • Returns -1 if the specified string value is not found.

Syntax

Signature Description
aString.lastIndexOf(searchValue[, fromIndex])Returns the index value for the first occurence of the specified string from the specified starting index.

Parameters

Parameter Description
searchValueA string value.
fromIndexAn integer between 0 and length of the string that defaults to the length of the string.
  • If this parameter is specified the string is searched backwards from this point to index 0.

Examples

The code below creates a repeating string and searches backwards through it as both the searchValue and fromIndex parameters are specified.


// Create alphabet string variable.
var repeatingString = 'abcdefabcdefabcdefabcdef';

// Return index of last occurrence of search string.
alert(repeatingString.lastIndexOf('ab', 14));

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Related Tutorials

JavaScript Basic Tutorials - Lesson 8 - Strings