y = 0; ad = new Array(y);
ad[y++] = '<a href="http://www.tsefang.net" target="_blank"><img src="http://www.tsefang.net/images/bannerd1.gif" border="0"></a>';
ad[y++] = '<a href="http://www.tsefang.net/chain.asp" target="_blank"><img src="http://www.tsefang.net/pop/images/jmbanner2.gif" border="0"></a>';
//Continue if more required
x = Math.floor(Math.random()*(y));
document.write(ad[x]);