function createCookie(name,value,days) {
        var expires;
        if (days) {
            var date = new Date();
            date.setTime(date.getTime()+(days*24*60*60*1000));
            expires = "; expires="+date.toGMTString();
        }
        else {
            expires = "";
        }
        document.cookie = name+"="+value+expires+"; path=/";
    }

    function readCookie(name) {
        var nameEQ = name + "=";
        var ca = document.cookie.split(';');
        for(var i=0;i < ca.length;i++) {
            var c = ca[i];
            while (c.charAt(0)==' ') c = c.substring(1,c.length);
            if (c.indexOf(nameEQ) === 0) return c.substring(nameEQ.length,c.length);
        }
        return null;
    }

    function eraseCookie(name) {
        createCookie(name,"",-1);
    }