//-- This example is from the book _JavaScript: The Definitive Guide_.    
//-- Written by David Flanagan.  Copyright (c) 1996 O'Reilly & Associates. 
//-- This example is provided WITHOUT WARRANTY either expressed or implied.
//-- You may study, use, modify, and distribute it for any purpose.        

// Arguments:
//   document: the Document object that the cookie is stored for.  Required.
//   name: a string that specifies a name for the cookie.  Required.
//   hours: an optional number that specifies the number of hours from now
//          that the cookie should expire.
//   path: an optional string that specifies the cookie path attribute.
//   domain: an optional string that specifies the cookie domain attribute.
//   secure: an optional boolean value that, if true, requests a secure cookie.
//
function Cookie(document, name, hours, path, domain, secure)
{
    // All the predefined properties of this object begin with '$'
	
    this.$document = document;
    this.$name = name;
    if (hours)
        this.$expiration = new Date((new Date()).getTime() + hours*3600000); //8760hrs per year
    else this.$expiration = null;
    if (path) this.$path = path; else this.$path = null;
    if (domain) this.$domain = domain; else this.$domain = null;
    if (secure) this.$secure = true; else this.$secure = false;
}

function _Cookie_store()
{
    var cookieval = "";
    for(var prop in this) {
        // ignore properties with names that begin with '$' and also methods
        if ((prop.charAt(0) == '$') || ((typeof this[prop]) == 'function')) 
            continue;
        if (cookieval != "") cookieval += '&';
        cookieval += prop + ':' + escape(this[prop]);
    }

    var cookie = this.$name + '=' + cookieval;
    if (this.$expiration)
        cookie += '; expires=' + this.$expiration.toGMTString();
    if (this.$path) cookie += '; path=' + this.$path;
    if (this.$domain) cookie += '; domain=' + this.$domain;
    if (this.$secure) cookie += '; secure';
	
	if (document.cookie != null) // for development case or for failing gracefully if cookies are off.
		document.cookie = cookie;
}

// This function is the load() method of the Cookie object
function _Cookie_load()
{
    // First, get a list of all cookies that pertain to this document.
    // We do this by reading the magic Document.cookie property
    var allcookies = document.cookie;
    if (allcookies == null || allcookies == "") return false;

    // Now extract just the named cookie from that list.
    var start = allcookies.indexOf(this.$name + '=');
    if (start == -1) return false;   // cookie not defined for this page.
    start += this.$name.length + 1;  // skip name and equals sign.
    var end = allcookies.indexOf(';', start);
    if (end == -1) end = allcookies.length;
    var cookieval = allcookies.substring(start, end);

    var a = cookieval.split('&');  // break it into array of name/value pairs
    for(var i=0; i < a.length; i++)  // break each pair into an array
        a[i] = a[i].split(':');

    for(var i = 0; i < a.length; i++) {
        this[a[i][0]] = unescape(a[i][1]);
    }

    return true;
}

function _Cookie_remove()
{
    var cookie;
    cookie = this.$name + '=';
    if (this.$path) cookie += '; path=' + this.$path;
    if (this.$domain) cookie += '; domain=' + this.$domain;
    cookie += '; expires=Fri, 02-Jan-1970 00:00:00 GMT';
	if (document.cookie != null) // for development case or for failing gracefully if cookies are off.
    	document.cookie = cookie;
}

new Cookie();
Cookie.prototype.store = _Cookie_store;
Cookie.prototype.load = _Cookie_load;
Cookie.prototype.remove = _Cookie_remove;