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URL: URL() constructor

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

js

new URL(url)
new URL(url, base)

Parameters

url

A string or any other object with a stringifier — including, for example, an <a> or <area> element — that represents 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 string 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 a string. 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

js

// Base URLs:
let baseUrl = "https://developer.mozilla.org";

let A = new URL("/", baseUrl);
// => 'https://developer.mozilla.org/'

let B = new URL(baseUrl);
// => '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'

// Invalid URLs:

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

// Other cases:

new URL("http://www.example.com");
// => 'http://www.example.com/'

new URL("http://www.example.com", B);
// => 'http://www.example.com/'

new URL("", "https://example.com/?query=1");
// => 'https://example.com/?query=1' (Edge before 79 removes query arguments)

new URL("/a", "https://example.com/?query=1");
// => 'https://example.com/a' (see relative URLs)

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

Specifications

Specification
URL Standard
# constructors

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
URL 19
12Before Edge 79, query arguments in the base URL argument are removed when calling the URL constructor.
26 No 15 14.1
6In Safari 14 and earlier, calling the URL constructor with a base URL whose value is undefined causes Safari to throw a TypeError; see WebKit bug 216841.
4.4 25 26 14 14.5
6In Safari 14 and earlier, calling the URL constructor with a base URL whose value is undefined causes Safari to throw a TypeError; see WebKit bug 216841.
1.5

See also

© 2005–2023 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/URL/URL