How to use ResizeObserver API In Javascript

Method 3: Using addEventListener() Method

We can use the latest ResizeObserver API to listen to the window resize event. This API is not fully supported.

Example: In this example, we are using ResizeObserver API.

javascript

<!DOCTYPE html>
<html>
<head>
    <title>
        How to detect and resize
        the window size
    </title>
     
    <style>
        body {
            text-align: center;
        }
        h1 {
            color:green;
        }
    </style>
</head>
 
<body>
    <h1>w3wiki</h1>
     
    <h3>
        Resizing the screen size and display its
        <br>corresponding width and height
    </h3>
    <div id="height">Height: <span></span></div>
    <div id="width">Width: <span></span></div>
     
    <script>
        const body = document.getElementsByTagName("body")[0];
         
        const height = document.querySelector("#height span");
        const width = document.querySelector("#width span");
 
        // Initialize resize observer object
        let resizeObserver = new ResizeObserver(() => {
             
            // Set the current height and width
            // to the element
            height.innerHTML = window.innerHeight;
            width.innerHTML = window.innerWidth;
         
        });
         
        // Add a listener to body
        resizeObserver.observe(body);
    </script>
</body>
</html>

Output:

How to detect when the window size is resized using JavaScript ?

Sometimes when we develop our site, we want to detect the size of the window, In this article, we are going to learn how to detect when the window size is resized using JavaScript

The window resize event occurs whenever the size of the browser window gets changed. We can listen to the resize event in two ways: