function commentbox() {
	var div = document.getElementById("commentformbox");
	if (div.className == "show") {
		div.className = "hide";
		document.getElementById("switching_mark").innerHTML = '<a href="javascript:commentbox();">コメントフォームを開く</a>';
	}else{
		div.className = "show";
		document.getElementById("switching_mark").innerHTML = '<a href="javascript:commentbox();">コメントフォームを閉じる×</a>';
	}
}