JavaScript array.keys() method

The JavaScript array.keys() creates an array iterator object having only the keys of an array

Following is the code for the array.keys() method −


 Live Demo

<!DOCTYPE html>
<html lang="en">
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
   body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
   .sample {
      font-size: 20px;
      font-weight: 500;
<h1>JavaScript array keys()</h1>
<div class="sample"></div>
<button class="Btn">CLICK HERE</button>
Click on the above button to see the keys of the array
   let fillEle = document.querySelector(".sample");
   let arr = ["H", "E", "L", "L", "O"];
   fillEle.innerHTML = arr;
   arr = arr.keys();
   document.querySelector(".Btn").addEventListener("click", () => {
      fillEle.innerHTML = "";
      for (let x of arr) {
         fillEle.innerHTML += x + "<br>";


On clicking the “CLICK HERE” button −