var url = document.URL;
var ja = true;
if (url.match(/_e\.htm/)) {
	ja = false;
}
if (document.URL.match(/.*\/$/)) {
	url = url + "index.htm";
}

if (ja) {
	var target = url.replace(/\.htm/,"_e.htm");
	document.write('Japanese | <a href="'+target+'">English</a>');
} else {
	var target = url.replace(/_e\.htm/,".htm");
	document.write('<a href="'+target+'">Japanese</a> | English');
}