url.js

window.url = (function() {
    function isNumeric(arg) {
      return !isNaN(parseFloat(arg)) && isFinite(arg);
    }
    
    return function(arg, url) {
        var _ls = url || window.decodeURI(window.location.toString());

        if (!arg) { return _ls; }
        else { arg = arg.toString(); }

        if (_ls.substring(0,2) === '//') { _ls = 'http:' + _ls; }
        else if (_ls.split('://').length === 1) { _ls = 'http://' + _ls; }

        url = _ls.split('/');
        var _l = {auth:''}, host = url[2].split('@');

        if (host.length === 1) { host = host[0].split(':'); }
        else { _l.auth = host[0]; host = host[1].split(':'); }

        _l.protocol=url[0];
        _l.hostname=host[0];
        _l.port=(host[1] || ((_l.protocol.split(':')[0].toLowerCase() === 'https') ? '443' : '80'));
        _l.pathname=( (url.length > 3 ? '/' : '') + url.slice(3, url.length).join('/').split('?')[0].split('#')[0]);
        var _p = _l.pathname;

        if (_p.charAt(_p.length-1) === '/') { _p=_p.substring(0, _p.length-1); }
        var _h = _l.hostname, _hs = _h.split('.'), _ps = _p.split('/');

        if (arg === 'hostname') { return _h; }
        else if (arg === 'domain') {
            if (/^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/.test(_h)) { return _h; }
            return _hs.slice(-2).join('.'); 
        }
        //else if (arg === 'tld') { return _hs.slice(-1).join('.'); }
        else if (arg === 'sub') { return _hs.slice(0, _hs.length - 2).join('.'); }
        else if (arg === 'port') { return _l.port; }
        else if (arg === 'protocol') { return _l.protocol.split(':')[0]; }
        else if (arg === 'auth') { return _l.auth; }
        else if (arg === 'user') { return _l.auth.split(':')[0]; }
        else if (arg === 'pass') { return _l.auth.split(':')[1] || ''; }
        else if (arg === 'path') { return _l.pathname; }
        else if (arg.charAt(0) === '.')
        {
            arg = arg.substring(1);
            if(isNumeric(arg)) {arg = parseInt(arg, 10); return _hs[arg < 0 ? _hs.length + arg : arg-1] || ''; }
        }
        else if (isNumeric(arg)) { arg = parseInt(arg, 10); return _ps[arg < 0 ? _ps.length + arg : arg] || ''; }
        else if (arg === 'file') { return _ps.slice(-1)[0]; }
        else if (arg === 'filename') { return _ps.slice(-1)[0].split('.')[0]; }
        else if (arg === 'fileext') { return _ps.slice(-1)[0].split('.')[1] || ''; }
        else if (arg.charAt(0) === '?' || arg.charAt(0) === '#')
        {
            var params = _ls, param = null;

            if(arg.charAt(0) === '?') { params = (params.split('?')[1] || '').split('#')[0]; }
            else if(arg.charAt(0) === '#') { params = (params.split('#')[1] || ''); }

            if(!arg.charAt(1)) { return params; }

            arg = arg.substring(1);
            params = params.split('&');

            for(var i=0,ii=params.length; i<ii; i++)
            {
                param = params[i].split('=');
                if(param[0] === arg) { return param[1] || ''; }
            }

            return null;
        }

        return '';
    };
})();

if(typeof jQuery !== 'undefined') {
    jQuery.extend({
        url: function(arg, url) { return window.url(arg, url); }
    });
}