JavaScript String indexOf() method
The JavaScript string indexOf() method is used to search the position of a particular character or string in a sequence of given char values. This 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 methods used to search the position of an element.
| Method | Description |
|---|---|
| indexOf(ch) | It returns the index position of char value passed with method. |
| indexOf(ch,index) | It start searching the element from the provided index value and then returns the index position of specified char value. |
| indexOf(str) | It returns the index position of first character of string passed with method. |
| indexOf(str,index) | It start 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”.
Return
Index of a particular character.
JavaScript String indexOf() 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:
2
Example 2
In this example, we will provide the index value from where the search starts.
Output:
7
Example 3
Here, we will print the position of a first character of string.
Output:
6
Example 4
In this example, we will provide the index value from where the search starts.
Output:
20
Example 5
Here, we will try to search the element by changing its case-sensitivity.
Output:
-1