if (document.images) {
	var img1 = new Image();
	img1.src = "/common/materials/nv_home.gif";
	var img2 = new Image();
	img2.src = "/common/materials/nv_clinic_on.gif";
	var img3 = new Image();
	img3.src = "/common/materials/nv_word.gif";
	var img4 = new Image();
	img4.src = "/common/materials/nv_news_on.gif";
}