var txt = new Array();
txt[0]="<a href='http://www.fishing-v.jp/charity/charity_info.html?link=top:topbanner 'title='釣りでつながろう、日本　Angler's AID'><img src='js/img/random_banner_charity.gif' border='0'></a>"

/*バナーを追加したらmmaxの数も増やす*/
mmax = 1;
txtno = Math.floor(Math.random() * mmax);
document.write(txt[txtno]);