line = 2;
banner = new Array(
'<a href="/topics/rank201103/topics.html?afid=lb-rank"><img class="mrg5d" src="/topics/rank201103/img/btn.jpg"></a>',
'<a href="/topics/rank201103/topics.html?afid=lb-rank"><img class="mrg5d" src="/topics/rank201103/img/btn.jpg"></a>'
);
rnd = Math.floor(Math.random()*line);
document.write(banner[rnd]);