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"
}

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

怎么样?

'https://stackoverflow.com/questions/736513/how-do-i-parse-a-url-into-hostname-and-path-in-javascript'.split('//').pop() .split('/')[0]

结果:

“stackoverflow.com”

freddiefujiwara的答案很好，但我也需要在ie中支持相对url。我想出了以下解决方案:

function getLocation(href) {
    var location = document.createElement("a");
    location.href = href;
    // IE doesn't populate all link properties when setting .href with a relative URL,
    // however .href will return an absolute URL which then can be used on itself
    // to populate these additional fields.
    if (location.host == "") {
      location.href = location.href;
    }
    return location;
};

现在使用它来获得所需的属性:

var a = getLocation('http://example.com/aa/bb/');
document.write(a.hostname);
document.write(a.pathname);

例子:

function getLocation(href) { var location = document.createElement("a"); location.href = href; // IE doesn't populate all link properties when setting .href with a relative URL, // however .href will return an absolute URL which then can be used on itself // to populate these additional fields. if (location.host == "") { location.href = location.href; } return location; }; var urlToParse = 'http://example.com/aa/bb/', a = getLocation(urlToParse); document.write('Absolute URL: ' + urlToParse); document.write('<br />'); document.write('Hostname: ' + a.hostname); document.write('<br />'); document.write('Pathname: ' + a.pathname);

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");