myImg=["http://cafe-shu.com/common/img/index_pict01.jpg","http://cafe-shu.com/common/img/index_pict02.jpg","http://cafe-shu.com/common/img/index_pict03.jpg","http://cafe-shu.com/common/img/index_pict04.jpg","http://cafe-shu.com/common/img/index_pict01.jpg","http://cafe-shu.com/common/img/index_pict01.jpg","http://cafe-shu.com/common/img/index_pict01.jpg"];
i=Math.random() * myImg.length;
myVal = Math.floor(i);
document.write('<style type="text/css"><!--div.index-main-image-area{background:url('+myImg[myVal]+') no-repeat;}--></style>');