JavaScript String indexOf(): Find Occurrence Position in String

In this tutorial, you will learn how to find the first occurrence of a character’s position in a string using the JavaScript string indexOf() method.

The indexOf() method in JavaScript is used to find the first occurrence of a character in a given string. It returns the position of the first occurrence of the character in the string. If the character is not found in the string, it returns -1.

The syntax for the indexOf() method is as follows:

str.indexOf(search_value, start)

Here,
str: The given string
search_value: The character or string to search in the given string
start: The optional parameter specifies where to start the search in a given string.

Example 1:

Let’s take an example of finding the first occurrence of the “de” character in the string “Hello developers, welcome to the JavaScript tutorial.”

const string = "Hello developers, welcome to the JavaScript tutorial.";<br>const res = string.indexOf("de");<br>console.log("Result of the above code is:-" + res);

Output: Result of the above code is:-6

Example 2:

Now let’s take an example of finding a character or string in a given string with a specific position. In this example, we will find the first occurrence of the “JavaScript” string in the given string starting from position 10.

const string = "Hello JavaScript developers, welcome to the JavaScript tutorial.";<br>const res = string.indexOf("JavaScript", 10);<br>console.log("Result of the above code is:-" + res);

Output: Result of the above code is:-44

In conclusion, the JavaScript string indexOf() method is useful in finding the first occurrence of a character or string in a given string. You can also use the start parameter to start the search from a specific position in the string.