那么简单的正则表达式呢?

url = "http://www.example.com/path/to/somwhere";
urlParts = /^(?:\w+\:\/\/)?([^\/]+)(.*)$/.exec(url);
hostname = urlParts[1]; // www.example.com
path = urlParts[2]; // /path/to/somwhere

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

对于那些正在寻找在IE, Firefox和Chrome中工作的现代解决方案的人:

这些使用超链接元素的解决方案都不会在chrome中起同样的作用。如果你传递一个无效(或空白)的url给chrome，它总是会返回脚本被调用的主机。所以在IE中你会得到空白，而在Chrome中你会得到localhost(或其他什么)。

如果你试图看着推荐人，这是骗人的。你需要确保你返回的主机在原始url中，以处理这个问题:

    function getHostNameFromUrl(url) {
        // <summary>Parses the domain/host from a given url.</summary>
        var a = document.createElement("a");
        a.href = url;

        // Handle chrome which will default to domain where script is called from if invalid
        return url.indexOf(a.hostname) != -1 ? a.hostname : '';
    }

跨浏览器的URL解析，围绕IE 6、7、8和9的相对路径问题工作:

function ParsedUrl(url) {
    var parser = document.createElement("a");
    parser.href = url;

    // IE 8 and 9 dont load the attributes "protocol" and "host" in case the source URL
    // is just a pathname, that is, "/example" and not "http://domain.com/example".
    parser.href = parser.href;

    // IE 7 and 6 wont load "protocol" and "host" even with the above workaround,
    // so we take the protocol/host from window.location and place them manually
    if (parser.host === "") {
        var newProtocolAndHost = window.location.protocol + "//" + window.location.host;
        if (url.charAt(1) === "/") {
            parser.href = newProtocolAndHost + url;
        } else {
            // the regex gets everything up to the last "/"
            // /path/takesEverythingUpToAndIncludingTheLastForwardSlash/thisIsIgnored
            // "/" is inserted before because IE takes it of from pathname
            var currentFolder = ("/"+parser.pathname).match(/.*\//)[0];
            parser.href = newProtocolAndHost + currentFolder + url;
        }
    }

    // copies all the properties to this object
    var properties = ['host', 'hostname', 'hash', 'href', 'port', 'protocol', 'search'];
    for (var i = 0, n = properties.length; i < n; i++) {
      this[properties[i]] = parser[properties[i]];
    }

    // pathname is special because IE takes the "/" of the starting of pathname
    this.pathname = (parser.pathname.charAt(0) !== "/" ? "/" : "") + parser.pathname;
}

使用方法(演示JSFiddle在这里):

var myUrl = new ParsedUrl("http://www.example.com:8080/path?query=123#fragment");

结果:

{
    hash: "#fragment"
    host: "www.example.com:8080"
    hostname: "www.example.com"
    href: "http://www.example.com:8080/path?query=123#fragment"
    pathname: "/path"
    port: "8080"
    protocol: "http:"
    search: "?query=123"
}

在acdcjunior解决方案上扩展了“searchParam”功能 模仿URL对象，增加了“searchParam”来解析查询字符串 适用于IE 6、7、8、9、10、11

用法- (JSFiddle Link)

// USAGE:
var myUrl = new ParsedUrl("http://www.example.com/path?var1=123&var2=abc#fragment");
console.log(myUrl);
console.log(myUrl.searchParam('var1'));
console.log(myUrl.searchParam('var2'));

输出- (JSFiddle链接)

{
  hash: "#fragment",
  host: "www.example.com:8080",
  hostname: "www.example.com",
  href: "http://www.example.com:8080/path?var1=123&var2=abc#fragment",
  pathname: "/path",
  port: "80",
  protocol: "http:",
  search: "?var1=123&var2=abc"
}

"123"
"abc"

CODE - (JSFiddle Link)

function ParsedUrl(url) {
    var parser = document.createElement("a");
    parser.href = url;
    
    // IE 8 and 9 dont load the attributes "protocol" and "host" in case the source URL
    // is just a pathname, that is, "/example" and not "http://www.example.com/example".
    parser.href = parser.href;
    
    // IE 7 and 6 wont load "protocol" and "host" even with the above workaround,
    // so we take the protocol/host from window.location and place them manually
    if (parser.host === "") {
        var newProtocolAndHost = window.location.protocol + "//" + window.location.host;
        if (url.charAt(1) === "/") {
            parser.href = newProtocolAndHost + url;
        } else {
            // the regex gets everything up to the last "/"
            // /path/takesEverythingUpToAndIncludingTheLastForwardSlash/thisIsIgnored
            // "/" is inserted before because IE takes it of from pathname
            var currentFolder = ("/"+parser.pathname).match(/.*\//)[0];
            parser.href = newProtocolAndHost + currentFolder + url;
        }
    }
    
    // copies all the properties to this object
    var properties = ['host', 'hostname', 'hash', 'href', 'port', 'protocol', 'search'];
    for (var i = 0, n = properties.length; i < n; i++) {
      this[properties[i]] = parser[properties[i]];
    }
    
    // pathname is special because IE takes the "/" of the starting of pathname
    this.pathname = (parser.pathname.charAt(0) !== "/" ? "/" : "") + parser.pathname;
  
  //search Params
  this.searchParam =  function(variable) {
    var query = (this.search.indexOf('?') === 0) ? this.search.substr(1) : this.search;
    var vars = query.split('&');
    for (var i = 0; i < vars.length; i++) {
        var pair = vars[i].split('=');
        if (decodeURIComponent(pair[0]) == variable) {
            return decodeURIComponent(pair[1]);
        }
    }
    console.log('Query variable %s not found', variable);
    return '';
    };
}

js-uri(在谷歌Code上可用)接受字符串URL并从中解析URI对象:

var some_uri = new URI("http://www.example.com/foo/bar");

alert(some_uri.authority); // www.example.com
alert(some_uri);           // http://www.example.com/foo/bar

var blah      = new URI("blah");
var blah_full = blah.resolve(some_uri);
alert(blah_full);         // http://www.example.com/foo/blah