// The constructor function: creates a cookie object for the specified
// document, with a specified name and optional attributes.
// 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 '$'
         // to distinguish them from other properties which are the values to
         // be stored in the cookie.
         this.$document = document;
         this.$name = name;
         if (hours)
                 this.$expiration = new Date((new Date()).getTime() + hours*3600000);
         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.$secure = false;
}
// This function is the store() method of the Cookie object.
function _Cookie_store()
{
         // First, loop through the properties of the Cookie object and
         // put together the value of the cookie. Since cookies use the
         // equals sign and semicolons as separators, we'll use colons
         // and ampersands for the individual state variables we store
         // within a single cookie value. Note that we escape the value
         // of each state variable, in case it contains punctuation or other
         // illegal characters.
         var cookieval = "";
         for(var prop in this) {
                 // Ignore properties with names that begin with '$' and also methods.
                 if ((prop.charAt(0) == '$') || ((typeof this[prop]) == 'function'))
                         continue;
                 if (cookieval != "") cookieval += '&';
                 cookieval += prop + ':' + escape(this[prop]);
         }
         // Now that we have the value of the cookie, put together the
         // complete cookie string, which includes the name, and the various
         // attributes specified when the Cookie object was created.
         var cookie = this.$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.$secure) cookie += '; secure';
         // Now store the cookie by setting the magic Document.cookie property.
         this.$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 = this.$document.cookie;
         if (allcookies == "") return false;
         // Now extract just the named cookie from that list.
         var start = allcookies.indexOf(this.$name + '=');
         if (start == -1) return false;                                 // cookie not defined for this page.
         start += this.$name.length + 1; // skip name and equals sign.
         var end = allcookies.indexOf(';', start);
         if (end == -1) end = allcookies.length;
         var cookieval = allcookies.substring(start, end);
         // Now that we've extracted the value of the named cookie, we've
         // got to break that value down into individual state variable
         // names and values. The name/value pairs are separated from each
         // other with ampersands, and the individual names and values are
         // separated from each other with colons. We use the split method
         // to parse everything.
	      var a = cookieval.split('&'); // break it into array of name/value pairs
	      for(var i=0; i < a.length; i++) // break each pair into an array
	              a[i] = a[i].split(':');
	      // Now that we've parsed the cookie value, set all the names and values
	      // of the state variables in this Cookie object. Note that we unescape()
	      // the property value, because we called escape() when we stored it.
	      for(var i = 0; i < a.length; i++) {
	              this[a[i][0]] = unescape(a[i][1]);
	      }
	      // We're done, so return the success code.
	      return true;
}
// This function is the remove() method of the Cookie object.
function _Cookie_remove()
{
      var cookie;
      cookie = this.$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';
      this.$document.cookie = cookie;
}
// Create a dummy Cookie object, so we can use the prototype object to make
// the functions above into methods.
new Cookie();
Cookie.prototype.store = _Cookie_store;
Cookie.prototype.load = _Cookie_load;
Cookie.prototype.remove = _Cookie_remove;