How to extract base URL from a string in JavaScript?

Question

Edit: Some complain that it doesn't take into account protocol. So I decided to upgrade the code, since it is marked as answer. For those who like one-line-code... well sorry this why we use code minimizers, code should be human readable and this way is better... in my opinion.

var pathArray = "https://somedomain.com".split( '/' );
var protocol = pathArray[0];
var host = pathArray[2];
var url = protocol + '//' + host;

Or use Davids solution from below.

WebKit-based browsers, Firefox as of version 21 and current versions of Internet Explorer (IE 10 and 11) implement location.origin.

location.origin includes the protocol, the domain and optionally the port of the URL.

For example, location.origin of the URL http://www.sitename.com/article/2009/09/14/this-is-an-article/ is http://www.sitename.com.

To target browsers without support for location.origin use the following concise polyfill:

if (typeof location.origin === 'undefined')
    location.origin = location.protocol + '//' + location.host;

Don't need to use jQuery, just use

location.hostname

There is no reason to do splits to get the path, hostname, etc from a string that is a link. You just need to use a link

//create a new element link with your link
var a = document.createElement("a");
a.href="http://www.sitename.com/article/2009/09/14/this-is-an-article/";

//hide it from view when it is added
a.style.display="none";

//add it
document.body.appendChild(a);

//read the links "features"
alert(a.protocol);
alert(a.hostname)
alert(a.pathname)
alert(a.port);
alert(a.hash);

//remove it
document.body.removeChild(a);

You can easily do it with jQuery appending the element and reading its attr.

Update: There is now new URL() which simplifies it

const myUrl = new URL("https://www.example.com:3000/article/2009/09/14/this-is-an-article/#m123")

const parts = ['protocol', 'hostname', 'pathname', 'port', 'hash'];

parts.forEach(key => console.log(key, myUrl[key]))

var host = location.protocol + '//' + location.host + '/';