line = 3;
banner = new Array(
'<a href=http://www.eic-book.com/filetop/filetop.php><img src=http://www.eic-book.com/eic_include/img/filesale.gif width=120 height=60 border=0 alt="ファイル販売"></a>',
'<a href=http://www.eic-book.com/list_4.html><img src=http://www.eic-book.com/eic_include/img/specialsales12060.gif width=120 height=60 border=0 alt="特典付きスペシャルセール"></a>',
'<a href=http://www.eic-book.com/yoyaku/index.html><img src=http://www.eic-book.com/eic_include/img/yoyaku12060.gif width=120 height=60 border=0 alt="先行予約発売"></a>'
);
rnd = Math.floor(Math.random()*line);
document.write(banner[rnd]);