JavaScript String lastIndexOf()

Search for the last occurrence of "planet":

let text = "Hello planet earth, you are a great planet.";
let result = text.lastIndexOf("planet");

let text = "Hello planet earth, you are a great planet.";
let result = text.lastIndexOf("Planet");

More examples below.

Description

The lastIndexOf() method returns the index (position) of the last occurrence of a specified value in a string.

The lastIndexOf() method searches the string from the end to the beginning.

The lastIndexOf() method returns the index from the beginning (position 0).

The lastIndexOf() method returns -1 if the value is not found.

The lastIndexOf() method is case sensitive.

string.lastIndexOf( searchvalue, start)

Parameter	Description
searchvalue	Required. The string to search for.
start	Optional. The position where to start. Default value is string length.

Type	Description
A number	The position where the search-value occurs. -1 if it never occurs.

Search for the last occurrence of "planet", starting at position 20:

let text = "Hello planet earth, you are a great planet.";
let result = text.lastIndexOf("planet", 20);

lastIndexOf() is an ECMAScript1 (ES1) feature.

ES1 (JavaScript 1997) is fully supported in all browsers:


Chrome	Edge	Firefox	Safari	Opera	IE
Yes	Yes	Yes	Yes	Yes	Yes