if (document.images) {
var img1on = new Image();
img1on.src = "http://magicbook.e-maga.jp/wp-content/themes/quality/images/logo2.gif";
var img1off = new Image();
img1off.src = "http://magicbook.e-maga.jp/wp-content/themes/quality/images/logo.gif";
}
function On(img1) { 
if (document.images) { 
document.images[img1].src = eval(img1 + 'on.src'); 
} 
}
function Off(img1) { 
if (document.images) { 
document.images[img1].src = eval(img1 + 'off.src'); 
} 
}