function getCookieValue(position) {
    var end = document.cookie.indexOf(";", position);
    if (end == -1)
        end = document.cookie.length;

    return unescape(document.cookie.substring(position, end));
}

function getCookie(name) {
    name += "=";
    var len = name.length;
    var cookie_len = document.cookie.length;
    var i = 0;
    while (i < cookie_len) {
    var j = i + len;
    if (document.cookie.substring(i, j) == name)
        return getCookieValue(j);
    i = document.cookie.indexOf(" ", i) + 1;
    if (i == 0)
        break;
    }
    return null;
}

function setCookie(name, value) {
    var arg_value = setCookie.arguments;
    var arg_len = setCookie.arguments.length;
    var expires = (arg_len > 2) ? arg_value[2] : null;
    var path = (arg_len > 3) ? arg_value[3] : null;
    var domain = (arg_len > 4) ? arg_value[4] : null;
    var secure = (arg_len > 5) ? arg_value[5] : false;
    document.cookie = name + "=" + escape (value) +
        ((expires == null) ? "" : ("; expires=" +
        expires.toGMTString())) +
        ((path == null) ? "" : ("; path=" + path)) +
        ((domain == null) ? "" : ("; domain=" + domain)) +
        ((secure == true) ? "; secure" : "");
}

function deleteCookie(name) {
    var exp = new Date();
    exp.setTime (exp.getTime() - 1);
    var cookie_value = getCookie(name);
    if (cookie_value != null)
        document.cookie = name + "=" + cookie_value +
            "; expires=" + exp.toGMTString();
}