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 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.

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

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, …

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 …

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 …

The JavaScript indexof method returns the index position of the first occurrence of a specified string. If the specified string is not found, the indexof function will return -1.

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

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

Jun 21, 2021 · The .indexOf() method returns the first index at which a specified element can be found in an array, or -1 if the element is not present. This method searches the array from left to right and …