ranimg = new Array();

ranimg[0]="/s/MP/cmn/images/bg_top_01.jpg";
ranimg[1]="/s/MP/cmn/images/bg_top_02.jpg";
ranimg[2]="/s/MP/cmn/images/bg_top_03.jpg";
ranimg[3]="/s/MP/cmn/images/bg_top_04.jpg";
ranimg[4]="/s/MP/cmn/images/bg_top_05.jpg";
ranimg[5]="/s/MP/cmn/images/bg_top_06.jpg";
ranimg[6]="/s/MP/cmn/images/bg_top_07.jpg";

xx = Math.floor(ranimg.length*Math.random());

ranimg = ranimg[Math.floor(xx)];

document.write ('<style type="text/css"><!--div.typeS div#mainContents {background-image: url("'+ ranimg +'");}--></style>');