What does the indexOf() method return if the element is not found in an array in JavaScript?Points:1-1null0undefinedI don't know

Breakdown of the Problem

1. Identify the function and its purpose.
2. Determine the return value when the specified element is not present in the array.

Relevant Concepts

• In JavaScript, the indexOf() method is used to search an array for a specified element and returns the first index at which the element can be found.

Analysis and Detail

1. Usage of indexOf():
   • If the element is found, it returns the index (a number).
   • If the element is not found, it returns -1, which is neither null, undefined, nor 0.

Verify and Summarize

• The options provided include null, 0, undefined, and the choice "I don't know".
• Based on the definition of indexOf(), if an element is not found, it will not return any of the specified options since it specifically returns -1.

Final Answer

The indexOf() method returns -1 if the element is not found in an array in JavaScript. Therefore, none of the provided options correctly represent the return value when an element is not found.