if (document.images) {

var img1on = new Image();
img1on.src = "image/top_2.gif";
var img1off = new Image();
img1off.src = "image/top_1.gif";

var img2on = new Image();
img2on.src = "image/info_2.gif";
var img2off = new Image();
img2off.src = "image/info_1.gif";

var img3on = new Image();
img3on.src = "image/history_2.gif";
var img3off = new Image();
img3off.src = "image/history_1.gif";

var img4on = new Image();
img4on.src = "image/profile_2.gif";
var img4off = new Image();
img4off.src = "image/profile_1.gif";

var img5on = new Image();
img5on.src = "image/photo_2.gif";
var img5off = new Image();
img5off.src = "image/photo_1.gif";

var img6on = new Image();
img6on.src = "image/re_2.gif";
var img6off = new Image();
img6off.src = "image/re_1.gif";

var img7on = new Image();
img7on.src = "image/diary_2.gif";
var img7off = new Image();
img7off.src = "image/diary_1.gif";

var img8on = new Image();
img8on.src = "image/bbs_2.gif";
var img8off = new Image();
img8off.src = "image/bbs_1.gif";

var img9on = new Image();
img9on.src = "image/link_2.gif";
var img9off = new Image();
img9off.src = "image/link_1.gif";

var img10on = new Image();
img10on.src = "image/contact_2.gif";
var img10off = new Image();
img10off.src = "image/contact_1.gif";

}

function On(name) { 

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

} 

function Off(name) { 

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

}