function setCookie(name, value, days) {
    var expireDate = new Date()    
    //set "expstring" to either future or past date, to set or delete cookie, respectively
    var expstring = (typeof days != "undefined") ? expireDate.setDate(expireDate.getDate() + parseInt(days)) : expireDate.setDate(expireDate.getDate() - 5)
    document.cookie = name + "=" + value + "; expires=" + expireDate.toGMTString() + "; path=/";    
}