How to Check if Variable is Object in Javascript

  • We have 3 elements in the HTML file (div, button, and h1). The div element is just a wrapper for the rest of the elements.
  • The inner text for the button element is “Check” and for the h1 element is “Result”.
  • We have done some basic styling using CSS and added the link to our style.css stylesheet inside the head element.
  • We have also included our javascript file script.js with a script tag at the bottom.
<!DOCTYPE html>
<html lang="en">
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <link rel="stylesheet" href="style.css">

    <script src="script.js"></script>
body {
    text-align: center;

div {
    display: inline-block;

button {
    display: inline-block;
    padding: 10px 20px;


  • We have selected 2 elements button and h1 using the document.querySelector() method and stored them in btnCheck and result variables respectively.
  • We have a global variable user and it holds an empty object as its value.
  • We have attached the click event listener to the button element.
  • In the event handler function, we are using typeof keyword to check if the user is an object or not. Point to be noted here is that null and arrays are also considered as an object.  That’s why we are using the logical AND (&&) operator and performing 3 checks to get the correct result.
  • The first check is to make sure that the user is an object.
  • The second check is to make sure that the user is not equal to null.
  • The third check is to make sure that the user is not an array.
  • After these 3 checks, we will get True in return and we will display it in the h1 element.
let btnCheck = document.querySelector('button');
let result = document.querySelector('h1');

let user = {};

btnCheck.addEventListener('click', () => {
    result.innerText = typeof user == 'object' && user != null && !Array.isArray(user) ? 'True' : 'False';