var flashurl = ["/swf/top1.swf", "/swf/top2.swf", "/swf/top3.swf", "/swf/top4.swf"];
flashurl = flashurl[Math.floor(Math.random() * flashurl.length)];
document.write('<object data="' + flashurl + '" type="application/x-shockwave-flash" width="950" height="310">');
document.write('<param value="' + flashurl + '" name="movie" /></object>');