// name = string equal to the name of the instance of the object
// defaultExpiration = number of units to make the default expiration date for the cookie
// expirationUnits = 'seconds' | 'minutes' | 'hours' | 'days' | 'months' | 'years' (default is 'days')
// defaultDomain = string, default domain for cookies; default is current domain minus the server name
// defaultPath = string, default path for cookies; default is '/'
function Cookiemanager(name,defaultExpiration,expirationUnits,defaultDomain,defaultPath) {
    // remember our name
    this.name = name;
    // get the default expiration
    this.defaultExpiration = this.getExpiration(defaultExpiration,expirationUnits);
    // set the default domain to defaultDomain if supplied; if not, set it to document.domain
    // if document.domain is numeric, otherwise strip off the server name and use the remainder
    this.defaultDomain = (defaultDomain)?defaultDomain:(document.domain.search(/[a-zA-Z]/) == -1)?document.domain:document.domain.substring(document.domain.indexOf('.') + 1,document.domain.length);
    // set the default path
    this.defaultPath = (defaultPath)?defaultPath:'/';
    // initialize an object to hold all the document's cookies
    this.cookies = new Object();
    // initialize an object to hold expiration dates for the doucment's cookies
    this.expiration = new Object();
    // initialize an object to hold domains for the doucment's cookies
    this.domain = new Object();
    // initialize an object to hold paths for the doucment's cookies
    this.path = new Object();
    // set an onlunload function to write the cookies
    window.onunload = new Function (this.name+'.setDocumentCookies();');
    // get the document's cookies
    this.getDocumentCookies();
    }
// gets an expiration date for a cookie as a GMT string
// expiration = integer expressing time in units (default is 7 days)
// units = 'miliseconds' | 'seconds' | 'minutes' | 'hours' | 'days' | 'months' | 'years' (default is 'days') 
Cookiemanager.prototype.getExpiration = function(expiration,units) {
    // set default expiration time if it wasn't supplied
    expiration = (expiration)?expiration:7;
    // supply default units if units weren't supplied
    units = (units)?units:'days';
    // new date object we'll use to get the expiration time
    var date = new Date();
    // set expiration time according to units supplied
    switch(units) {
        case 'years':
            date.setFullYear(date.getFullYear() + expiration);
            break;
        case 'months':
            date.setMonth(date.getMonth() + expiration);
            break;
        case 'days':
            date.setTime(date.getTime()+(expiration*24*60*60*1000));
            break;
        case 'hours':
            date.setTime(date.getTime()+(expiration*60*60*1000));
            break;
        case 'minutes':
            date.setTime(date.getTime()+(expiration*60*1000));
            break;
        case 'seconds':
            date.setTime(date.getTime()+(expiration*1000));
            break;
        default:
            date.setTime(date.getTime()+expiration);
            break;
        }
    // return expiration as GMT string
    return date.toGMTString();
    }
// gets all document cookies and populates the .cookies property with them
Cookiemanager.prototype.getDocumentCookies = function() {
    var cookie,pair;
    // read the document's cookies into an array
    var cookies = document.cookie.split(';');
    // walk through each array element and extract the name and value into the cookies property
    var len = cookies.length;
    for(var i=0;i < len;i++) {
        cookie = cookies[i];
        // strip leading whitespace
        while (cookie.charAt(0)==' ') cookie = cookie.substring(1,cookie.length);
        // split name/value pair into an array
        pair = cookie.split('=');
        // use the cookie name as the property name and value as the value
        this.cookies[pair[0]] = pair[1];
        }
    }
// sets all document cookies
Cookiemanager.prototype.setDocumentCookies = function() {
    var expires = '';
    var cookies = '';
    var domain = '';
    var path = '';
    for(var name in this.cookies) {
        // see if there's a custom expiration for this cookie; if not use default
        expires = (this.expiration[name])?this.expiration[name]:this.defaultExpiration;
        // see if there's a custom path for this cookie; if not use default
        path = (this.path[name])?this.path[name]:this.defaultPath;
        // see if there's a custom domain for this cookie; if not use default
        domain = (this.domain[name])?this.domain[name]:this.defaultDomain;
        // add to cookie string
        cookies = name + '=' + this.cookies[name] + '; expires=' + expires + '; path=' + path + '; domain=' + domain;
        document.cookie = cookies;
        }
    return true;
    }
// gets cookie value
// cookieName = string, cookie name
Cookiemanager.prototype.getCookie = function(cookieName) {
    var cookie = this.cookies[cookieName]
    return (cookie)?cookie:false;
    }
// stores cookie value, expiration, domain and path
// cookieName = string, cookie name
// cookieValue = string, cookie value
// expiration = number of units in which the cookie should expire
// expirationUnits = 'miliseconds' | 'seconds' | 'minutes' | 'hours' | 'days' | 'months' | 'years' (default is 'days')
// domain = string, domain for cookie
// path = string, path for cookie
Cookiemanager.prototype.setCookie = function(cookieName,cookieValue,expiration,expirationUnits,domain,path) {
    this.cookies[cookieName] = cookieValue;
    // set the expiration if it was supplied 
    if (expiration) this.expiration[cookieName] = this.getExpiration(expiration,expirationUnits);
    // set path if it was supplied
    if (domain) this.domain[cookieName] = domain;
    if (path) this.path[cookieName] = path;
    return true;
    }
var cookieManager = new Cookiemanager('cookieManager',1,'years');