June 20, 2020

How to Get Hostname from URL in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to get hostname from url in javascript. Hostname represents a domain name assigned to a computer. Each domain name points to a specific IP address.

Whenever you enter a domain name in the navigation bar, the browser sends a request to the DNS provider which resolves it to an IP address and loads the website.

There are various ways to extract a hostname from a URL string. You must have seen most of the solutions on the internet recommend using regex to do so but there is no universal solution that can extract a domain as well as a subdomain from a URL string.

To accomplish our goal, we are going to use a URL object. This object has a hostname property that will return a domain or subdomain depending upon the URL string.

In the following example, we will enter a random URL in the input field. Upon click of a button, we will extract the hostname and display it on the screen. Please have a look over the code example and the steps given below.

HTML & CSS

We have 4 elements in the HTML file (div, input, button, and h1). The div element is just a wrapper for the rest of the elements.
The button element and the h1 element have “Get” and “Result” as innerText respectively. The innerText of the h1 element will be updated dynamically using javascript.
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">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <link rel="stylesheet" href="style.css">
    <title>Document</title>
</head>
<body>
    
    <div>
        <input type="text">
        <button>Get</button>
        <h1>Result</h1>
    </div>

    <script src="script.js"></script>
</body>
</html>

body {
    text-align: center;
}

div {
    display: inline-block;
}

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

Javascript

We have selected the input, button, and h1 elements using the document.querySelector() method and stored them in the input, btnGet, and result variables respectively.
We have attached a click event listener to the button element.
In the event handler function, we are getting the value from the input element using value property and storing it in the value variable.
We are using the URL constructor to create an instance of a URL object and we are passing it the value variable as a parameter. The URL object is stored in the url variable.
We are using the hostname property to get the hostname from url and displaying it in the h1 element using the innerText property.

let input = document.querySelector('input');
let btnGet = document.querySelector('button');
let result = document.querySelector('h1');

btnGet.addEventListener('click', () => {
    let value = input.value;

    let url = new URL(value);

    result.innerText = url.hostname;
});

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