/*
Script Name: Javascript Cookie Script
Author: Public Domain, with some modifications
Script Source URI: http://techpatterns.com/downloads/javascript_cookies.php
Version 1.0.0
Last Update: 30 May 2004

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
*/

// this function gets the cookie, if it exists
function Get_Cookie( name ) {
	
	var start = document.cookie.indexOf( name + "=" );
	var len = start + name.length + 1;
	if ( ( !start ) && ( name != document.cookie.substring( 0, name.length ) ) )
	{
		return null;
	}
	if ( start == -1 ) return null;
	var end = document.cookie.indexOf( ";", len );
	if ( end == -1 ) end = document.cookie.length;
	return unescape( document.cookie.substring( len, end ) );
}

/*
only the first 2 parameters are required, the cookie name, the cookie
value. Cookie time is in milliseconds, so the below expires will make the 
number you pass in the Set_Cookie function call the number of days the cookie
lasts, if you want it to be hours or minutes, just get rid of 24 and 60.

Generally you don't need to worry about domain, path or secure for most applications
so unless you need that, leave those parameters blank in the function call.
*/
function Set_Cookie( name, value, expires, path, domain, secure ) {
	// set time, it's in milliseconds
	var today = new Date();
	today.setTime( today.getTime() );
	// if the expires variable is set, make the correct expires time, the
	// current script below will set it for x number of days, to make it
	// for hours, delete * 24, for minutes, delete * 60 * 24
	if ( expires )
	{
		expires = expires * 1000 * 60 * 60 * 24;
	}
	//alert( 'today ' + today.toGMTString() );// this is for testing purpose only
	var expires_date = new Date( today.getTime() + (expires) );
	//alert('expires ' + expires_date.toGMTString());// this is for testing purposes only

	document.cookie = name + "=" +escape( value ) +
		( ( expires ) ? ";expires=" + expires_date.toGMTString() : "" ) + //expires.toGMTString()
		( ( path ) ? ";path=" + path : "" ) + 
		( ( domain ) ? ";domain=" + domain : "" ) +
		( ( secure ) ? ";secure" : "" );
}

// this deletes the cookie when called
function Delete_Cookie( name, path, domain ) {
	if ( Get_Cookie( name ) ) document.cookie = name + "=" +
			( ( path ) ? ";path=" + path : "") +
			( ( domain ) ? ";domain=" + domain : "" ) +
			";expires=Thu, 01-Jan-1970 00:00:01 GMT";
}



<!--
//
//  Cookie Functions -- "Night of the Living Cookie" Version (25-Jul-96)
//
//  Written by:  Bill Dortch, hIdaho Design <bdortch@hidaho.com>
//  The following functions are released to the public domain.
//
//  This version takes a more aggressive approach to deleting
//  cookies.  Previous versions set the expiration date to one
//  millisecond prior to the current time; however, this method
//  did not work in Netscape 2.02 (though it does in earlier and
//  later versions), resulting in "zombie" cookies that would not
//  die.  DeleteCookie now sets the expiration date to the earliest
//  usable date (one second into 1970), and sets the cookie's value
//  to null for good measure.
//
//  Also, this version adds optional path and domain parameters to
//  the DeleteCookie function.  If you specify a path and/or domain
//  when creating (setting) a cookie**, you must specify the same
//  path/domain when deleting it, or deletion will not occur.
//
//  The FixCookieDate function must now be called explicitly to
//  correct for the 2.x Mac date bug.  This function should be
//  called *once* after a Date object is created and before it
//  is passed (as an expiration date) to SetCookie.  Because the
//  Mac date bug affects all dates, not just those passed to
//  SetCookie, you might want to make it a habit to call
//  FixCookieDate any time you create a new Date object:
//
//    var theDate = new Date();
//    FixCookieDate (theDate);
//
//  Calling FixCookieDate has no effect on platforms other than
//  the Mac, so there is no need to determine the user's platform
//  prior to calling it.
//
//  This version also incorporates several minor coding improvements.
//
//  **Note that it is possible to set multiple cookies with the same
//  name but different (nested) paths.  For example:
//
//    SetCookie ("color","red",null,"/outer");
//    SetCookie ("color","blue",null,"/outer/inner");
//
//  However, GetCookie cannot distinguish between these and will return
//  the first cookie that matches a given name.  It is therefore
//  recommended that you *not* use the same name for cookies with
//  different paths.  (Bear in mind that there is *always* a path
//  associated with a cookie; if you don't explicitly specify one,
//  the path of the setting document is used.)
//  
//  Revision History:
//
//    "Toss Your Cookies" Version (22-Mar-96)
//      - Added FixCookieDate() function to correct for Mac date bug
//
//    "Second Helping" Version (21-Jan-96)
//      - Added path, domain and secure parameters to SetCookie
//      - Replaced home-rolled encode/decode functions with Netscape's
//        new (then) escape and unescape functions
//
//    "Free Cookies" Version (December 95)
//
//
//  For information on the significance of cookie parameters, and
//  and on cookies in general, please refer to the official cookie
//  spec, at:
//
//      http://www.netscape.com/newsref/std/cookie_spec.html    
//
//******************************************************************
//
// "Internal" function to return the decoded value of a cookie
//
function getCookieVal (offset) {
  var endstr = document.cookie.indexOf (";", offset);
  if (endstr == -1)
    endstr = document.cookie.length;
  return unescape(document.cookie.substring(offset, endstr));
}
//
//  Function to correct for 2.x Mac date bug.  Call this function to
//  fix a date object prior to passing it to SetCookie.
//  IMPORTANT:  This function should only be called *once* for
//  any given date object!  See example at the end of this document.
//
function FixCookieDate (date) {
  var base = new Date(0);
  var skew = base.getTime(); // dawn of (Unix) time - should be 0
  if (skew > 0)  // Except on the Mac - ahead of its time
    date.setTime (date.getTime() - skew);
}
//
//  Function to return the value of the cookie specified by "name".
//    name - String object containing the cookie name.
//    returns - String object containing the cookie value, or null if
//      the cookie does not exist.
//
function GetCookie (name) {
  var arg = name + "=";
  var alen = arg.length;
  var clen = document.cookie.length;
  var i = 0;
  while (i < clen) {
    var j = i + alen;
    if (document.cookie.substring(i, j) == arg)
      return getCookieVal (j);
    i = document.cookie.indexOf(" ", i) + 1;
    if (i == 0) break; 
  }
  return null;
}
//
//  Function to create or update a cookie.
//    name - String object containing the cookie name.
//    value - String object containing the cookie value.  May contain
//      any valid string characters.
//    [expires] - Date object containing the expiration data of the cookie.  If
//      omitted or null, expires the cookie at the end of the current session.
//    [path] - String object indicating the path for which the cookie is valid.
//      If omitted or null, uses the path of the calling document.
//    [domain] - String object indicating the domain for which the cookie is
//      valid.  If omitted or null, uses the domain of the calling document.
//    [secure] - Boolean (true/false) value indicating whether cookie transmission
//      requires a secure channel (HTTPS).  
//
//  The first two parameters are required.  The others, if supplied, must
//  be passed in the order listed above.  To omit an unused optional field,
//  use null as a place holder.  For example, to call SetCookie using name,
//  value and path, you would code:
//
//      SetCookie ("myCookieName", "myCookieValue", null, "/");
//
//  Note that trailing omitted parameters do not require a placeholder.
//
//  To set a secure cookie for path "/myPath", that expires after the
//  current session, you might code:
//
//      SetCookie (myCookieVar, cookieValueVar, null, "/myPath", null, true);
//
function SetCookie (name,value,expires,path,domain,secure) {
  document.cookie = name + "=" + escape (value) +
    ((expires) ? "; expires=" + expires.toGMTString() : "") +
    ((path) ? "; path=" + path : "") +
    ((domain) ? "; domain=" + domain : "") +
    ((secure) ? "; secure" : "");
}

//  Function to delete a cookie. (Sets expiration date to start of epoch)
//    name -   String object containing the cookie name
//    path -   String object containing the path of the cookie to delete.  This MUST
//             be the same as the path used to create the cookie, or null/omitted if
//             no path was specified when creating the cookie.
//    domain - String object containing the domain of the cookie to delete.  This MUST
//             be the same as the domain used to create the cookie, or null/omitted if
//             no domain was specified when creating the cookie.
//
function DeleteCookie (name,path,domain) {
  if (GetCookie(name)) {
    document.cookie = name + "=" +
      ((path) ? "; path=" + path : "") +
      ((domain) ? "; domain=" + domain : "") +
      "; expires=Thu, 01-Jan-70 00:00:01 GMT";
  }
}

//
//  Examples - Unremark if you want to see how this code works
/*
var expdate = new Date ();
FixCookieDate (expdate); // Correct for Mac date bug - call only once for given Date object!
expdate.setTime (expdate.getTime() + (24 * 60 * 60 * 1000)); // 24 hrs from now 
SetCookie ("ccpath", "http://www.hidaho.com/colorcenter/", expdate);
SetCookie ("ccname", "hIdaho Design ColorCenter", expdate);
SetCookie ("tempvar", "This is a temporary cookie.");
SetCookie ("ubiquitous", "This cookie will work anywhere in this domain",null,"/");
SetCookie ("paranoid", "This cookie requires secure communications",expdate,"/",null,true);
SetCookie ("goner", "This cookie must die!");
document.write (document.cookie + "<br>");
DeleteCookie ("goner");
document.write (document.cookie + "<br>");
document.write ("ccpath = " + GetCookie("ccpath") + "<br>");
document.write ("ccname = " + GetCookie("ccname") + "<br>");
document.write ("tempvar = " + GetCookie("tempvar") + "<br>");
*/
// -->