JavaScript String lastIndexOf() method
The JavaScript string lastIndexOf() method is used to search the position of a particular character or string in a sequence of given char values. It behaves similar to indexOf() method with a difference that it start searching an element from the last position of the string.
The lastIndexOf() method is case-sensitive. The index position of first character in a string is always starts with zero. If an element is not present in a string, it returns -1.
Syntax
These are the following ways used to search the position of an element.
Method | Description |
---|---|
lastIndexOf(ch) | It returns the last index position of char value passed with method. |
lastIndexOf(ch,index) | It starts searching the element from the provided index value in the inverse order and then returns the index position of specified char value. |
lastIndexOf(str) | It returns the index position of first character of string passed with method. |
lastIndexOf(str,index) | It starts searching the element from the provided index value and then returns the index position of first character of string. |
Parameters
ch – It represent the single character to search like ‘a’.
index – It represent the index position from where search starts.
str – It represent the string to search like “Java”.
JavaScript String lastIndexOf() method example
Let’s see the various ways of searching the position of an element with help of simple examples.
Example 1
Here, we will print the position of a single character.
Output:
23
Example 2
In this example, we will provide the index value from where the search starts.
Output:
21
Example 3
Here, we will print the position of a first character of string.
Output:
20
Example 4
In this example, we will provide the index value from where the search starts.
Output:
6
Example 5
Here, we will try to search the element by changing its case-sensitivity.
Output:
-1