Умный переключатель языков

<ul>
   <li><a onclick="return switch_language('ru', 'ru')" href="/ru/">ru</a></li>
   <li><a onclick="return switch_language('ru', 'en')" href="/en/">en</a></li>
   <li><a onclick="return switch_language('ru', 'cn')" href="/cn/">cn</a></li>
</ul>

/ Аналог РНР-функции str_replace

function str_replace( search, replace, subject ) {

	if ( !( replace instanceof Array ) ) {
		replace = new Array( replace );
		if ( search instanceof Array ) {
			while ( search.length > replace.length ) {
				replace[ replace.length ] = replace[ 0 ];
			}
		}
	}

	if ( !( search instanceof Array ) ) search = new Array( search );
	while ( search.length > replace.length ) {
		replace[ replace.length ] = '';
	}

	if ( subject instanceof Array ) {
		for ( k in subject ) {
			subject[ k ] = str_replace( search, replace, subject[ k ] );
		}
		return subject;
	}

	for ( var k = 0; k - 1 ) {
		subject = subject.replace( search[ k ], replace[ k ] );
		i = subject.indexOf( search[ k ], i );
	}
}

return subject;

}

// Аналог РНР-функции parse_url
function parse_url( str, component ) {

	var o = {
			strictMode: false,
			key: [ "source", "protocol", "authority", "userInfo", "user", "password", "host", "port", "relative", "path", "directory", "file", "query", "anchor" ],
			q: {
				name: "queryKey",
				parser: /(?:^|&)([^&=]<em>)=?([^&]</em > ) / g
		},
		parser: {
			strict: /^(?:([^:\/?#]+):)?(?:\/\/((?:(([^:@]<em>):?([^:@]</em > ) ) ? @ ) ? ( [ ^: \/?#]<em>)(?::(\d</em > ) ) ? ) ) ? ( ( ( ( ? : [ ^ ? #\/]<em>\/)</em > )( [ ^ ? # ] < em > ) )( ? : \ ? ( [ ^ # ] < /em>))?(?:#(.<em>))?)/,
			loose: /^(?:(?![^:@]+:[^:@\/]</em > @ )( [ ^: \/?#.]+):)?(?:\/\/\/?)?((?:(([^:@]<em>):?([^:@]</em > ) ) ? @ ) ? ( [ ^: \/?#]<em>)(?::(\d</em > ) ) ? )( ( ( \/(?:<a href="?![^?#\/]*.[^?#\/.]+(?:[?#]|$)">^?#</a > ) < em > \/?)?([^?#\/]</em > ) )( ? : \ ? ( [ ^ # ] < em > ) ) ? ( ? : #( . < /em>))?)/ // Added one optional slash to post-protocol to catch file:/// (should restrict this)
			}
		};

		var m = o.parser[ o.strictMode ? "strict" : "loose" ].exec( str ),
			uri = {},
			i = 14;
		while ( i-- ) {
			uri[ o.key[ i ] ] = m[ i ] || "";
		}
		switch ( component ) {
		case 'PHP_URL_SCHEME':
			return uri.protocol;
		case 'PHP_URL_HOST':
			return uri.host;
		case 'PHP_URL_PORT':
			return uri.port;
		case 'PHP_URL_USER':
			return uri.user;
		case 'PHP_URL_PASS':
			return uri.password;
		case 'PHP_URL_PATH':
			return uri.path;
		case 'PHP_URL_QUERY':
			return uri.query;
		case 'PHP_URL_FRAGMENT':
			return uri.anchor;
		default:
			var retArr = {};
			if ( uri.protocol !== '' ) {
				retArr.scheme = uri.protocol;
			}
			if ( uri.host !== '' ) {
				retArr.host = uri.host;
			}
			if ( uri.port !== '' ) {
				retArr.port = uri.port;
			}
			if ( uri.user !== '' ) {
				retArr.user = uri.user;
			}
			if ( uri.password !== '' ) {
				retArr.pass = uri.password;
			}
			if ( uri.path !== '' ) {
				retArr.path = uri.path;
			}
			if ( uri.query !== '' ) {
				retArr.query = uri.query;
			}
			if ( uri.anchor !== '' ) {
				retArr.fragment = uri.anchor;
			}
			return retArr;
		}
	}

	// Собственно, само переключение
	function switch_language( from, to ) {
		// Если языки совпадают - пропустить
		if ( from == to ) return false;
		// Получить УРЛ
		var url = document.location.href;
		// Распарсить
		var purl = parse_url( url );
		// Взять ток путь
		var path = purl.path;
		var nurl;
		// Вариант для главной страницы
		if ( path == '/' ) {
			nurl = url + to + '/';
			// Для внутренних страниц
		} else {
			nurl = str_replace( '/' + from + '/', '/' + to + '/', url );
			//nurl = url.replace(/from/, to);
		}
		// Переход по новому адресу
		document.location.href = nurl;
		return false;
	}