if (document.images) {

var img1on = new Image();
img1on.src = "/image/navi/home-on.jpg";
var img1off = new Image();
img1off.src = "/image/navi/home.jpg";

var img2on = new Image();
img2on.src = "/image/navi/service-on.jpg";
var img2off = new Image();
img2off.src = "/image/navi/service.jpg";

var img3on = new Image();
img3on.src = "/image/navi/what-on.jpg";
var img3off = new Image();
img3off.src = "/image/navi/what.jpg";

var img4on = new Image();
img4on.src = "/image/navi/company-on.jpg";
var img4off = new Image();
img4off.src = "/image/navi/company.jpg";

var img5on = new Image();
img5on.src = "/image/navi/mail-on.jpg";
var img5off = new Image();
img5off.src = "/image/navi/mail.jpg";

var img6on = new Image();
img6on.src = "/image/left-menu-simmu-on.jpg";
var img6off = new Image();
img6off.src = "/image/left-menu-simmu.jpg";

var img7on = new Image();
img7on.src = "/image/left-menu-otorihiki-on.jpg";
var img7off = new Image();
img7off.src = "/image/left-menu-otorihiki.jpg";

var img8on = new Image();
img8on.src = "/image/left-menu-faq-on.jpg";
var img8off = new Image();
img8off.src = "/image/left-menu-faq.jpg";

var img9on = new Image();
img9on.src = "/image/left-menu-caution-on.jpg";
var img9off = new Image();
img9off.src = "/image/left-menu-caution.jpg";

}

function on(id) { if (document.images) { document.images[id].src = eval(id + 'on.src'); } }
function off(id) { if (document.images) { document.images[id].src = eval(id + 'off.src'); } }