var rand = Math.floor(Math.random()*4);
rand = rand+1;
document.write("<style>body { background-color: #dddddd; background-image:url(images/body"+rand+".jpg); background-position: top center; background-repeat:repeat-y; background-attachment:fixed; margin-top: 0px; margin-left: 0px; margin-right: 0px; margin-bottom: 20px; text-align: center; }</style>")