function addEngine(){
	if ((typeof window.sidebar == "object") && (typeof window.sidebar.addSearchEngine == "function")){
		window.sidebar.addSearchEngine(
			"http://ferret-plus.com/fptools/ff/ferret-plus.src",
			"http://ferret-plus.com/fptools/ferret-plus.png",
			"Ferret+",
			"Search" );
	}
	else{
		alert("FireFoxをご利用の場合のみ追加できます。");
	}
}