ranimg = new Array();
ranimg[0]="http://www.think-agent.co.jp/mt-custom/css/images/top-content/top-picture-01.jpg";
ranimg[1]="http://www.think-agent.co.jp/mt-custom/css/images/top-content/top-picture-02.jpg";
ranimg[2]="http://www.think-agent.co.jp/mt-custom/css/images/top-content/top-picture-03.jpg";
xx = Math.floor(ranimg.length*Math.random());
ranimg = ranimg[Math.floor(xx)];
document.write ('<style type="text/css">#image-area {background-image: url("'+ ranimg +'");}--></style>');