Jul 10, 2025 · The indexOf() method of Array instances returns the first index at which a given element can be found in the array, or -1 if it is not present.

Description The indexOf() method returns the position of the first occurrence of a value in a string. The indexOf() method returns -1 if the value is not found. The indexOf() method is case sensitive.

Jul 8, 2025 · Learn how to use indexOf () in JavaScript with syntax, examples, best practices, and comparisons with includes (). Perfect for beginners. Tagged with javascript, webdev, beginners, …

In this tutorial, you'll learn how to use the JavaScript String indexOf () method to find the index of a substring within a string.

indexOf () Return Value Returns the first index of the element in the array if it is present at least once. Returns -1 if the element is not found in the array. Note: indexOf() compares searchElement to …

The JavaScript array indexOf method is a quick and reliable way to determine the position of an element in an array, especially when working with primitive types like numbers and strings.

Returns the index of the first occurrence of a value in an array.

Sep 30, 2024 · The indexOf () method in JavaScript is used to find the index of the first occurrence of a specified value within a string. The method returns a 0-based index, making it a fundamental …

Feb 5, 2025 · A comprehensive guide to the JavaScript String indexOf () method, explaining how to find the index of a substring within a string.

Dec 19, 2022 · In this article, we will explore how to use the indexOf method with both arrays and strings, including how to specify a starting index for the search and how to use the indexOf method …