The fill() method is used to fill all the elements of an array with a specified value. It modifies the original array and does not create a new one. The syntax is as follows: array.fill(value, start, end); - value: The value to fill the array with. - start (optional): The index to start filling the array. Default is 0. - end (optional): The index to stop filling the array. Default is the length of the array. Here's a simple example: let myArray = [1, 2, 3, 4, 5]; myArray.fill(0, 2, 4); console.log(myArray); // Output: [1, 2, 0, 0, 5] In this example, the elements at indices 2 and 3 are filled with the value 0.