function forumSetCookie(name, value, expire) {
    document.cookie = name + "=" + escape(value) + "; path=/"
        + ((expire == null) ? "" : ("; expires=" + expire.toGMTString()))
}

function forumGetCookie(Name) {
    var search = Name + "=";
    if (document.cookie.length > 0) { 
       offset = document.cookie.indexOf(search);
       if (offset != -1) { 
           offset += search.length;
           end = document.cookie.indexOf(";", offset); 
           if (end == -1) {
               end = document.cookie.length;
           } 
           return unescape(document.cookie.substring(offset, end));
        }  
    }

    return -1;
}

var t = new Date();
var expires = new Date()
expires.setTime(t.getTime() + 1000*60*60*24*365)

var cookie = forumGetCookie("FORUM_VISIT");

if (cookie == -1) {
    visit_begun = t.getTime();
    last_visit  = t.getTime();
    forumSetCookie("FORUM_VISIT", visit_begun + "," + last_visit, expires);
} else {
    timestamps = cookie.split(",");
    visit_begun = timestamps[0];
    last_visit = timestamps[1];
    if (t.getTime() - visit_begun > 60*15*1000) {
        last_visit = visit_begun;
        visit_begun = t.getTime();
        forumSetCookie("FORUM_VISIT", visit_begun + "," + last_visit, expires);
    }
}

num_images = document.images.length;

for (i = 0; i < num_images; i++) {
    var img_name = document.images[i].name;

    if (img_name.substring(0, 6) == "forum_") {
        var time = img_name.substring(6);

        if (time > last_visit) {
            document.images[i].src = '/images/forum/new.gif';
            document.images[i].width = 20;
            document.images[i].height = 20;
        } else {
            document.images[i].src = '/s.gif';
            document.images[i].width = 0;
        }
    }
}