var rnd = Math.round(Math.random()*10);

if (rnd>=0 && rnd<=3) {
  document.writeln('<iframe src="http://rcm.amazon.com/e/cm?t=punklyrics-20&o=1&p=48&l=st1&mode=music&search=punk&fc1=000000&lt1=_blank&lc1=3366FF&bg1=FFFFFF&npa=1&f=ifr" marginwidth="0" marginheight="0" width="728" height="90" border="0" frameborder="0" style="border:none;" scrolling="no"></iframe>');
}
else if (rnd>=4 && rnd<=7) {
  document.writeln('<iframe src="http://rcm.amazon.com/e/cm?t=punklyrics-20&o=1&p=48&l=ur1&category=game_downloads&banner=1DDSH9AY7GF9CF8DZN02&f=ifr" width="728" height="90" scrolling="no" border="0" marginwidth="0" style="border:none;" frameborder="0"></iframe>');
}
else {
  document.writeln('<iframe src="http://rcm.amazon.com/e/cm?t=punklyrics-20&o=1&p=26&l=ur1&category=school&banner=0VVVE587DSFVFKWQNT82&f=ifr" width="468" height="60" scrolling="no" border="0" marginwidth="0" style="border:none;" frameborder="0"></iframe>');
}