The URL interface is used to parse, construct, normalize, and encode URLs. It works by providing properties which allow you to easily read and modify the components of a URL.
You normally create a new URL object by specifying the URL as a string when calling its constructor, or by providing a relative URL and a base URL. You can then easily read the parsed components of the URL or make changes to the URL.
If a browser doesn't yet support the URL() constructor, you can access a URL object using the Window interface's URL property. Be sure to check to see if any of your target browsers require this to be prefixed.
The constructor takes a url parameter, and an optional base parameter to use as a base if the url parameter is a relative URL:
const url = new URL('../cats', 'http://www.example.com/dogs');
console.log(url.hostname);
console.log(url.pathname);
URL properties can be set to construct the URL:
url.hash = 'tabby';
console.log(url.href);
URLs are encoded according to the rules found in RFC 3986. For instance:
url.pathname = 'démonstration.html';
console.log(url.href);
The URLSearchParams interface can be used to build and manipulate the URL query string.
To get the search params from the current window's URL, you can do this:
const parsedUrl = new URL(window.location.href);
console.log(parsedUrl.searchParams.get("id"));
The toString() method of URL just returns the value of the href property, so the constructor can be used to normalize and encode a URL directly.
const response = await fetch(new URL('http://www.example.com/démonstration.html'));
