function getCookie(name) {
        var prefix = name + "=";
        var cookieStartIndex = document.cookie.indexOf(prefix);
        if (cookieStartIndex == -1) return null;
        var cookieEndIndex = document.cookie.indexOf(";", cookieStartIndex + prefix.length);
        if (cookieEndIndex == -1) cookieEndIndex = document.cookie.length;
        return unescape(document.cookie.substring(cookieStartIndex + prefix.length, cookieEndIndex));
}
function setCookie(name, value, expires) {
        if (expires == 'permanent'){
                expires = 'Fri, 25 Dec 2099 23:59:59 GMT';
        } else {
                ((expires) ? "; expires=" + expires.toGMTString() : "");
        }
        var curCookie = name + "=" + escape(value) + ((expires) ? "; expires=" + expires : "") + "; path=/";
        document.cookie = curCookie;
}
function delCookie(name)
{
        document.cookie = name + "=; expires=Fri, 31 Dec 1999 23:59:59 GMT; path=/";
}