var img = new Array();

img[801] = new Image();  img[801].src="http://www.nissinka.co.jp/images/menu_about.gif";
img[802] = new Image();  img[802].src="http://www.nissinka.co.jp/images/menu_about_.gif";
img[803] = new Image();  img[803].src="http://www.nissinka.co.jp/images/menu_news.gif";
img[804] = new Image();  img[804].src="http://www.nissinka.co.jp/images/menu_news_.gif";

function change_image(nam,num) {
        if(navigator.appVersion.charAt(0)>= 3) {
                document.images[nam].src = img[num].src;
        }
}