This page contains the following code, which sets the document's background based on the previous page's selection:

<script type="text/javascript">
//Get cookie routine by Shelley Powers 
function get_cookie(Name) {
var search = Name + "="
var returnvalue = "";
if (document.cookie.length > 0) {
offset = document.cookie.indexOf(search)
// if cookie exists
if (offset != -1) { 
offset += search.length
// set index of beginning of value
end = document.cookie.indexOf(";", offset);
// set index of end of cookie value
if (end == -1) end = document.cookie.length;
returnvalue=unescape(document.cookie.substring(offset, end))
}
}
return returnvalue;
}
if (get_cookie("bgcolor")!="")
document.body.style.backgroundColor=get_cookie("bgcolor")

</script>