var swfs = new Array("banner_vert.swf", "banner_autobahn.swf", "banner_vertical_150X500_abril.swf", "banner_vertical_2_abril.swf", "banner_0906.swf");

function randomizar(a){
  return a[Math.floor(Math.random() * a.length)];
}
swf=randomizar(swfs);
movie = "<object width=\"150\" height=\"500\">"
movie =movie + " <param name=\"wmode\"></param>"
movie =movie + " <param name=\"transparent\"></param>"
movie =movie + "<param name=\"movie\"  value=\"" + swf + "\"></param>"
movie =movie + "<embed src=\"" + swf + "\" type=\"application/x-shockwave-flash\" wmode=\"transparent\" width=\"150\" height=\"500\"></embed>"
movie =movie + "</object>"
document.write(movie);