URL: URL() constructor
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.
Note: This feature is available in Web Workers.
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.
Syntax
new URL(url)
new URL(url, base)
Parameters
url
-
A string or any other object with a stringifier that represents an absolute URL or a relative reference to a base URL. If
url
is a relative reference,base
is required, and is used to resolve the final URL. Ifurl
is an absolute URL, a givenbase
will not be used to create the resulting URL. base
Optional-
A string representing the base URL to use in cases where
url
is a relative reference. If not specified, it defaults toundefined
.When a
base
is specified, the resolved URL is not simply a concatenation ofurl
andbase
. Relative references to the parent and current directory are resolved are relative to the current directory of thebase
URL, which includes path segments up until the last forward-slash, but not any after. Relative references to the root are resolved relative to the base origin. For more information see Resolving relative references to a URL.
Note: The url
and base
arguments will each be stringified from whatever value you pass, such as an HTMLAnchorElement
or HTMLAreaElement
element, 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 be stringified from the object's href
property.
Exceptions
TypeError
-
url
(in the case of absolute URLs) orbase
+url
(in the case of relative references) is not a valid URL.
Examples
Here are some examples of using the constructor.
Note: Resolving relative references to a URL provides additional examples demonstrating how different url
and base
values are resolved to a final absolute URL.
// 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'
Here are some examples of 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 # dom-url-url |
Browser compatibility
BCD tables only load in the browser
See also
URL.parse()
, a non-throwing alternative to this constructor- Polyfill of
URL
incore-js
- The interface it belongs to:
URL
.