URL()

The URL() constructor returns a newly created URL object representing the URL defined by the parameters.

If the given base URL or the resulting URL are not valid URLs, the JavaScript TypeError exception is thrown.

Note:

This feature is available in Web Workers.

Syntax

const url = new URL(url [, base])

Parameters

url
A USVString representing an absolute or relative URL. If url is a relative URL, base is required, and will be used as the base URL. If url is an absolute URL, a given base will be ignored.
base Optional
A USVString representing the base URL to use in cases where url is a relative URL. If not specified, it defaults to undefined.

Note: The url and base arguments will each be stringified from whatever value you pass, just like with other Web APIs that accept USVString. In particular, you can use an existing URL object for either argument, and it will stringify to the object's href property.

Exceptions

Exception Explanation
TypeError url (in the case of absolute URLs) or base + url (in the case of relative URLs) is not a valid URL.

Examples

// Base urls
let m = 'https://developer.mozilla.org';
let a = new URL("/", m);                                // => 'https://developer.mozilla.org/'
let b = new URL(m);                                     // => 'https://developer.mozilla.org/'

        new URL('en-US/docs', b);                      // => 'https://developer.mozilla.org/en-US/docs'
let d = new URL('/en-US/docs', b);                     // => 'https://developer.mozilla.org/en-US/docs'
        new URL('/en-US/docs', d);                     // => 'https://developer.mozilla.org/en-US/docs'
        new URL('/en-US/docs', a);                     // => 'https://developer.mozilla.org/en-US/docs'

        new URL('/en-US/docs', "https://developer.mozilla.org/fr-FR/toto");
                                                       // => 'https://developer.mozilla.org/en-US/docs'

        new URL('/en-US/docs', '');                    // Raises a TypeError exception as '' is not a valid URL
        new URL('/en-US/docs');                        // Raises a TypeError exception as '/en-US/docs' is not a valid URL
        new URL('http://www.example.com', );           // => 'http://www.example.com/'
        new URL('http://www.example.com', b);          // => 'http://www.example.com/'

        new URL("//foo.com", "https://example.com")    // => 'https://foo.com' (see relative URLs)

Specifications

Specification Status Comment
URL
The definition of 'URL.URL()' in that specification.
Living Standard Initial definition.

Browser compatibility

BCD tables only load in the browser

See also

  • The interface it belongs to: URL.