function addToCookie(name, value) {
    var currentValue = getCookie(name);
    setCookie(name, currentValue + ',' + value + ',');
   
}

function setCookie(name, value)
{
    //If name is the empty string, it places a ; at the beginning
    //of document.cookie, causing clearCookies() to malfunction.
    if(name != '')
        document.cookie = name + '=' + value;
}

function getCookie(name)
{
    //Without this, it will return the first value
    //in document.cookie when name is the empty string.
    if(name == '')
        return('');

    name_index = document.cookie.indexOf(name + '=');

    if(name_index == -1)
        return('');

    cookie_value =  document.cookie.substr(name_index + name.length + 1,
        document.cookie.length);

    //All cookie name-value pairs end with a semi-colon, except the last one.
    end_of_cookie = cookie_value.indexOf(';');
    if(end_of_cookie != -1)
        cookie_value = cookie_value.substr(0, end_of_cookie);

    //Restores all the blank spaces.
    space = cookie_value.indexOf('+');
    while(space != -1)
    {
        cookie_value = cookie_value.substr(0, space) + ' ' +
        cookie_value.substr(space + 1, cookie_value.length);

        space = cookie_value.indexOf('+');
    }

    return(cookie_value);
}

function clearCookie(name)
{
    expires = new Date();
    expires.setYear(expires.getYear() - 1);

    document.cookie = name + '=null' + '; expires=' + expires;
}