JavaScript String indexOf() method

The JavaScript string indexOf() method retrieves the position of a char value present in the given string. It is case-sensitive.

Syntax 1:

string.indexOf(char) 

Syntax 2:

string.indexOf(ch,index) 

Syntax 3:

string.indexOf(str)

Syntax 4:

string.indexOf(str,index)

Parameters:
char: It represents the specified char like “c”.
str: It represents the specified string like “w3spoint”.
index: It represents the specified position from where search have to start.

Return:
It will returns the position of a char value if char is present in the string otherwise returns -1.

Example:

<!DOCTYPE html>
<html>
<body>
<script>   
var a ="Best tutorial website: w3spoint";  
document.write(a.indexOf('e'));  
document.write("</br>"); 
document.write(a.indexOf('e', 4)); 
document.write("</br>"); 
document.write(a.indexOf("es")); 
document.write("</br>"); 
document.write(a.indexOf("es", 4)); 
</script>
</body>
</html>

Output:

1
15
1
26
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