Set a cookie expire after 3 hours
I have this JavaScript code:
function createCookie(name,value,days) {
    if (days) {
        var date = new Date();
        date.setTime(date.getTime()+(days*2*60*60*1000));        
        var expires = "; expires="+date.toGMTString();
    }
    else var expires = "";
    document.cookie = name+"="+value+expires+"; path=/";
}
How can I make the cookie expire after 3 hours?