[devote]

Самый простейший вариант:

function parse_url( url ) {

	var parts = url.split( "#" ),
		out = {};

	out.url = url;
	out.hash = ( parts.length > 1 ? ( ( url = parts.shift() ) || 1 ) && parts.join( "#" ) : "" );
	url = ( parts = url.split( "?" ) ).shift();
	out.search = parts.join( "?" );
	out.scheme = ( parts = url.split( "://" ) ) && parts.length > 1 ? parts.shift() : "";
	out.host = ( ( parts = parts.join( "://" ).split( "/" ) ) && parts.length > 1 &&
					parts[0].indexOf(".") > 0 || out.scheme ) && parts.shift() || "";
	out.script = parts.pop();
	out.path = ( parts.length > 0 ? "/" : "" ) + parts.join( "/" );

	return out;
}

var out = parse_url( prompt( "Введите URL: ", "http://somesite.com/folder/index.php?param=value#lalala" ) );

alert([
	"url: " + out.url,
	"scheme: " + out.scheme,
	"host: " + out.host,
	"path: " + out.path,
	"script: " + out.script,
	"search: " + out.search,
	"hash: " + out.hash
].join("\n"));