if( document.images ) {
	var b1a = new Image;
	var b2a = new Image;
	var b3a = new Image;
	var b4a = new Image;
	var b5a = new Image;
	var b6a = new Image;
	b1a.src = "img/nav/b1a_ja.gif";
	b2a.src = "img/nav/b2a_ja.gif";
	b3a.src = "img/nav/b3a_ja.gif";
	b4a.src = "img/nav/b4a_ja.gif";
	b5a.src = "img/nav/b5a_ja.gif";
	b6a.src = "img/nav/b6a_ja.gif";
}