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 “w3schools”.
index: It represents the specified position from where the search has to start.
Return:
It will return the position of a char value if a char is present in the string otherwise returns -1.
Example:
<!DOCTYPE html>
<html>
<body>
<script>
var a ="Best tutorial website: w3schools";
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>