function random_rec() {
banner = new Array();
banner[0]="/shared/bnr/rectangle_01.jpg";
banner[1]="/shared/bnr/rectangle_02.jpg";
message = new Array();
message[0]="ありがとう掲示板";
message[1]="今月のプレゼント";
link = new Array();
link[0] = "/bbs/";
link[1] = "https://www.kazenoashiato.jp/present/";
rand = Math.floor(Math.random()*banner.length);
document.write("<p><a href="+link[rand]+"><img alt="+message[rand]+" src="+banner[rand]+" style='border-style:none'></a></p>");
}