var backgrounds = new Array()
backgrounds[0] = '/page/-/images/wrapper/background-1.jpg'
backgrounds[1] = '/page/-/images/wrapper/background-2a.jpg'
var j = 0
var p = backgrounds.length;
var preBuffer = new Array()
for (i = 0; i < p; i++){
   preBuffer[i] = new Image()
   preBuffer[i].src = backgrounds[i]
}
var whichImage = Math.round(Math.random()*(p-1));
function showImage(){
   document.write('<style type="text/css">body { background: url('+backgrounds[whichImage]+') no-repeat top center;} </style>');
}