rdmimg=new Array();
rdmimg[0]="images/main.png";
rdmimg[1]="images/main02.png";
rdmhead=Math.floor(rdmimg.length*Math.random());
rdmimg=rdmimg[Math.floor(rdmhead)];
document.write ('<style type="text/css">#main_contents{background: url('+rdmimg+') no-repeat center center; height:452px;}</style>');