function changeLanguage(fromLang, toLang)
{
	var defaultExtension = ".html";
	var defaultPage      = "index";
	var fLang = "/"+fromLang+"/";
	var tLang = "/"+toLang+"/";
	var s = (document.location.href) ? document.location.href: document.location;
	
	// find the language subfolder, i.e. "/en/index.htm";
	if (s.indexOf(fLang)>-1)
		var d = s.replace(fLang, tLang);
	else
	{
		// no language folder
		// find pages with suffix, i.e. "/index_en.htm"
		var pos = s.indexOf("_"+fromLang);
		if (pos>-1)
			var d = s.replace("_"+fromLang, "_"+toLang);
		else
		{
			// no suffix, find .htm extension
			// if found, convert e.g. index.htm to index_en.htm 
			// if not found, just go to index_en.htm
			pos = s.indexOf(defaultExtension);
			if (pos>-1)
				var d = s.replace(defaultExtension, "_"+toLang+defaultExtension);
			else
				var d = s+defaultPage+"_"+toLang+defaultExtension;
		}
	}
	
	if (document.location.href)
		document.location.href = d;
	else
		document.location = d;
}