Bill Dortch's Cookie Functions
/*
JavaScript Bible, Fourth Edition
by Danny Goodman
Publisher: John Wiley & Sons CopyRight 2001
ISBN: 0764533428
*/
<html>
<head>
<title>Cookie Functions</title>
</head>
<body>
<script language="javascript">
<!-- begin script
//
// 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 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=.uregina.ca" : "") +
((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=.uregina.ca" : "") +
"; expires=Thu, 01-Jan-70 00:00:01 GMT";
}
}
//
// Examples
//
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>");
// end script -->
</script>
</body>
</html>
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