/**
* This is the Cookie( ) constructor function.
*
* This constructor looks for a cookie with the specified name for the
* current document. If one exists, it parses its value into a set of
* name/value pairs and stores those values as properties of the newly created
* object.
*
* To store new data in the cookie, simply set properties of the Cookie
* object. Avoid properties named "store" and "remove", since these are
* reserved as method names.
*
* To save cookie data in the web browser's local store, call store( ).
* To remove cookie data from the browser's store, call remove( ).
*
* The static method Cookie.enabled( ) returns true if cookies are
* enabled and returns false otherwise.
*/
function Cookie(name) {
   this.$name = name;  // Remember the name of this cookie

   // First, get a list of all cookies that pertain to this document.
   // We do this by reading the magic Document.cookie property.
   // If there are no cookies, we don't have anything to do.
   var allcookies = document.cookie;
   if (allcookies == "") return;

   // Break the string of all cookies into individual cookie strings
   // Then loop through the cookie strings, looking for our name
   var cookies = allcookies.split(';');
   var cookie = null;
   for (var i = 0; i < cookies.length; i++) {
      // Does this cookie string begin with the name we want?
      var c = cookies[i];
      while (c.charAt(0) == ' ') c = c.substring(1, c.length); // remove whitespace
      if (c.indexOf(name + "=") == 0) {
         cookie = cookies[i];
         break;
      }
   }

   // If we didn't find a matching cookie, quit now
   if (cookie == null) return;

   // The cookie value is the part after the equals sign
   var cookieval = cookie.substring(name.length + 2);

   // Now that we've extracted the value of the named cookie, we
   // must break that value down into individual state variable
   // names and values. The name/value pairs are separated from each
   // other by ampersands, and the individual names and values are
   // separated from each other by colons. We use the split( ) method
   // to parse everything.
   var a = cookieval.split('&'); // Break it into an 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
   // as properties of this Cookie object. Note that we decode
   // the property value because the store( ) method encodes it.
   for (var i = 0; i < a.length; i++) {
      this[a[i][0]] = decodeURIComponent(a[i][1]);
   }
}

/**
* This function is the store( ) method of the Cookie object.
*
* Arguments:
*
*   daysToLive: the lifetime of the cookie, in days. If you set this
*     to zero, the cookie will be deleted. If you set it to null, or
*     omit this argument, the cookie will be a session cookie and will
*     not be retained when the browser exits. This argument is used to
*     set the max-age attribute of the cookie.
*   path: the value of the path attribute of the cookie
*   domain: the value of the domain attribute of the cookie
*   secure: if true, the secure attribute of the cookie will be set
*/
Cookie.prototype.store = function(daysToLive, path, domain, secure) {
   // 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 encode the value
   // of each property 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 + ':' + encodeURIComponent(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 (daysToLive || daysToLive == 0) {
      cookie += "; max-age=" + (daysToLive * 24 * 60 * 60);
   }

   if (path) cookie += "; path=" + path;
   if (domain) cookie += "; domain=" + domain;
   if (secure) cookie += "; secure";

   // Now store the cookie by setting the magic Document.cookie property
   document.cookie = cookie;
}

/**
* This function is the remove( ) method of the Cookie object; it deletes the
* properties of the object and removes the cookie from the browser's
* local store.
*
* The arguments to this function are all optional, but to remove a cookie
* you must pass the same values you passed to store( ).
*/
Cookie.prototype.remove = function(path, domain, secure) {
   // Delete the properties of the cookie
   for (var prop in this) {
      if (prop.charAt(0) != '$' && typeof this[prop] != 'function')
         delete this[prop];
   }

   // Then, store the cookie with a lifetime of 0
   this.store(0, path, domain, secure);
}

/**
* This static method attempts to determine whether cookies are enabled.
* It returns true if they appear to be enabled and false otherwise.
* A return value of true does not guarantee that cookies actually persist.
* Nonpersistent session cookies may still work even if this method
* returns false.
*/
Cookie.enabled = function() {
   // Use navigator.cookieEnabled if this browser defines it
   if (navigator.cookieEnabled != undefined) return navigator.cookieEnabled;

   // If we've already cached a value, use that value
   if (Cookie.enabled.cache != undefined) return Cookie.enabled.cache;

   // Otherwise, create a test cookie with a lifetime
   document.cookie = "testcookie=test; max-age=10000";  // Set cookie

   // Now see if that cookie was saved
   var cookies = document.cookie;
   if (cookies.indexOf("testcookie=test") == -1) {
      // The cookie was not saved
      return Cookie.enabled.cache = false;
   }
   else {
      // Cookie was saved, so we've got to delete it before returning
      document.cookie = "testcookie=test; max-age=0";  // Delete cookie
      return Cookie.enabled.cache = true;
   }
}