javascript cookie 存，取，刪操作

        //獲得Cookie解碼後的值
        function GetCookieVal(offset)
        {
            var endstr = document.cookie.indexOf (";", offset);
            if (endstr == -1)
                endstr = document.cookie.length;
            return unescape(document.cookie.substring(offset, endstr));
        }
       
        //設定Cookie值
        function SetCookie(name, value)
        {
            var expdate = new Date();
            var argv = SetCookie.arguments;
            var argc = SetCookie.arguments.length;
            alert(argc);
            var expires = (argc > 2) ? argv[2] : null;
            var path = (argc > 3) ? argv[3] : null;
            var domain = (argc > 4) ? argv[4] : null;
            var secure = (argc > 5) ? argv[5] : false;
            if(expires!=null) expdate.setTime(expdate.getTime() + ( expires * 1000 ));
            document.cookie = name + "=" + escape (value) +((expires == null) ? "" : ("; expires="+ expdate.toGMTString()))
            +((path == null) ? "" : ("; path=" + path)) +((domain == null) ? "" : ("; domain=" + domain))
            +((secure == true) ? "; secure" : "");
        }
       
        //刪除Cookie
        function DelCookie(name)
        {
            var exp = new Date();
            exp.setTime (exp.getTime() - 1);
            var cval = GetCookie (name);
            document.cookie = name + "=" + cval + "; expires="+ exp.toGMTString();
        }
       
        //獲得Cookie的原始值
        function GetCookie(name)
        {
            var arg = name + "=";
            var alen = arg.length;
            var clen = document.cookie.length;
            var i = 0;
            while (i < clen)
            {
                var j = i + alen;
                if (document.cookie.substring(i, j) == arg)
                return GetCookieVal (j);
                i = document.cookie.indexOf(" ", i) + 1;
                if (i == 0)
                    break;
            }
            return null;
        }