第一个答案的简单破解

var getLocation = function(href=window.location.href) {
    var l = document.createElement("a");
    l.href = href;
    return l;
};

即使没有参数，也可以使用它来计算当前的主机名 getLocation()。Hostname将给出当前主机名

在这里找到:https://gist.github.com/jlong/2428561

var parser = document.createElement('a');
parser.href = "http://example.com:3000/pathname/?search=test#hash";

parser.protocol; // => "http:"
parser.host;     // => "example.com:3000"
parser.hostname; // => "example.com"
parser.port;     // => "3000"
parser.pathname; // => "/pathname/"
parser.hash;     // => "#hash"
parser.search;   // => "?search=test"
parser.origin;   // => "http://example.com:3000"

var getLocation = function(href) {
    var l = document.createElement("a");
    l.href = href;
    return l;
};
var l = getLocation("http://example.com/path");
console.debug(l.hostname)
>> "example.com"
console.debug(l.pathname)
>> "/path"

别再白费力气了。使用https://github.com/medialize/URI.js/

var uri = new URI("http://example.org:80/foo/hello.html");
// get host
uri.host(); // returns string "example.org:80"
// set host
uri.host("example.org:80");

你也可以使用来自Locutus项目(前php.js)的parse_url()函数。

代码:

parse_url('http://username:password@hostname/path?arg=value#anchor');

结果:

{
  scheme: 'http',
  host: 'hostname',
  user: 'username',
  pass: 'password',
  path: '/path',
  query: 'arg=value',
  fragment: 'anchor'
}

function parseUrl(url) {
    var m = url.match(/^((?:([^:\/?#]+:)(?:\/\/))?((?:([^\/?#:]*):([^\/?#:]*)@)?([^\/?#:]*)(?::([^\/?#:]*))?))?([^?#]*)(\?[^#]*)?(#.*)?$/),
        r = {
            hash: m[10] || "",                   // #asd
            host: m[3] || "",                    // localhost:257
            hostname: m[6] || "",                // localhost
            href: m[0] || "",                    // http://username:password@localhost:257/deploy/?asd=asd#asd
            origin: m[1] || "",                  // http://username:password@localhost:257
            pathname: m[8] || (m[1] ? "/" : ""), // /deploy/
            port: m[7] || "",                    // 257
            protocol: m[2] || "",                // http:
            search: m[9] || "",                  // ?asd=asd
            username: m[4] || "",                // username
            password: m[5] || ""                 // password
        };
    if (r.protocol.length == 2) {
        r.protocol = "file:///" + r.protocol.toUpperCase();
        r.origin = r.protocol + "//" + r.host;
    }
    r.href = r.origin + r.pathname + r.search + r.hash;
    return r;
};
parseUrl("http://username:password@localhost:257/deploy/?asd=asd#asd");

它既适用于绝对url，也适用于相对url