bg = new Array(2);
bg[0] = 'backgroundindex/start01.jpg';
bg[1] = 'backgroundindex/start02.jpg';
bg[2] = 'backgroundindex/start03.jpg';
bg[3] = 'backgroundindex/start04.jpg';
bg[4] = 'backgroundindex/start05.jpg';
bg[5] = 'backgroundindex/start06.jpg';
index = Math.floor(Math.random() * bg.length);
document.write("<style>TABLE.randombg{background-image: url('"+bg[index]+"');}</style>");