myImg=["/common/img/main_pict_04.jpg","/common/img/main_pict_06.jpg","/common/img/main_pict_03.jpg","/common/img/main_pict_05.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>');