function changeLang(lang){
	var url = window.location.pathname;
	filename = url.substring(url.lastIndexOf("/") + 1, url.length);
	if (location.hash != "")
	{
		filename += location.hash;
	}
	switch(lang)
	{
	case "en":
		self.location="../en/"+filename;
		break;
	case "big5":
		self.location="../"+filename;
		break;
	case "gb":
		self.location=filename;
		break;
	}
}