I'm working on setting cookies for a website and I've been having trouble getting it right. When I check DevTools on my browser (Chrome), I'm always getting messages about the SameSite attribute being unspecified. Would anyone be able to help out?
const dropCookie = true;
const cookieDays = 14;
const cookieName = "Compliance";
const cookieState = "on";
const banner = document.getElementById("cookie-banner");
const displayBanner = () => {
const main = document.getElementsByTagName("main")[0];
banner.style.display = "flex";
main.className += " cookie-banner";
createCookie(window.cookieName, window.cookieState, window.cookieDays);
}
const createCookie = (name, value, days) => {
let cookie = name + "=" + encodeURIComponent(value);
if (typeof days === "number") {
const date = new Date();
date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
const expires = "expires=" + date.toUTCString();
}
if (window.dropCookie) {
cookie = `${name}=${value}; ${expires}; path=/; secure; samesite=none`
document.cookie = cookie;
}
}
function checkCookie(name) {
const nameEq = `${name}=`;
const cookieArr = document.cookie.split(";");
for (let i = 0; i < cookieArr.length; i++) {
let c = cookieArr[i];
while (c.charAt(0) == " ") c = c.substring(1, c.length);
if (c.indexOf(nameEq) == 0) return c.substring(nameEq.length, c.length);
}
return null;
}
function eraseCookie(name) {
createCookie(name, "", -1);
}
window.onload = () => {
if (checkCookie(window.cookieName) != window.cookieState) {
displayBanner();
}
}
I found that there were several reference errors being thrown from my code. I had to correct the instances where I referenced variables as properties of window, and also fix the Unix to UTC time conversion in createCookie.
const dropCookie = true;
const cookieDays = 14;
const cookieName = "compliance";
const cookieState = "on";
const banner = document.getElementById("cookie-banner");
const displayBanner = () => {
const main = document.getElementsByTagName("main")[0];
banner.style.display = "flex";
main.className += " cookie-banner";
createCookie(cookieName, cookieState, cookieDays);
}
const closeBanner = () => {
banner.style.display = "none";
}
const createCookie = (name, value, days) => {
let cookie = name + "=" + encodeURIComponent(value);
if (typeof days === "number") {
let date = new Date();
let unixDate = date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
date = new Date(unixDate);
const expires = "expires=" + date.toUTCString();
if (dropCookie) {
document.cookie = `${name}=${value}; ${expires}; path=/; secure; samesite=lax`
}
}
}
Lastly, I fixed the window.onload statement by saving the function to a variable windowInit, then calling it in window.onload.
const windowInit = () => {
if (checkCookie(cookieName) != cookieState) {
displayBanner();
}
}
window.onload = windowInit();
I have this code:
var CookieHelper = function () {
return {
GetCookie : function (cookieName) {
var cookieNameRequest = cookieName + "=";
var cookiesCollection = document.cookie.split(";");
for (var i = 0; i < cookiesCollection.length; i++) {
var cookieValuePair = cookiesCollection[i];
while (cookieValuePair.charAt(0) == " ") cookieValuePair = cookieValuePair.substring(1, cookieValuePair.length);
if (cookieValuePair.indexOf(cookieNameRequest) == 0)
return cookieValuePair.substring(cookieNameRequest.length, cookieValuePair.length);
}
return null;
},
DeleteCookie : function (cookieName) {
CookieHelper.SetCookie(cookieName, "", -1);
},
SetCookie : function (cookieName, cookieValue, cookieExpirationDays) {
var tmpDate = new Date;
if (cookieExpirationDays) {
tmpDate.setTime(tmpDate.getTime() + cookieExpirationDays * 24 * 60 * 60 * 1000);
var expires = "; expires=" + tmpDate.toGMTString();
} else {
// if cookieExpirationDays isn't set cookie will expire at the end of the day
var expirationTime = new Date(tmpDate.getFullYear(), tmpDate.getMonth(), tmpDate.getDate(), 23, 59, 59);
var expires = "; expires=" + expirationTime.toGMTString();
}
document.cookie = cookieName + "=" + cookieValue + expires + "; path=/;" + (location.protocol === "https:" ? "secure=true" : "");
}
};
}();
and I need to write unit tests for GetCookie.
I tried with:
QUnit.module('Cookie Helper Tests');
QUnit.test('GetCookie - returns no cookie', function(assert) {
var stub = sinon.spy(CookieHelper, 'GetCookie');
var cookieName = 'testCookieName';
var cookieValue = CookieHelper.GetCookie(cookieName);
assert.ok(cookieValue == null, 'returns no cookie');
});
I need to mock/stub document.cookie but I am completely new with Sinon and QUnit.
Can someone give me explanation what I did wrong?
Thanks in advance!
Srdjan
Well actually you can't mock properties with Sinon and more over you cannot mock the document.cookies property as it's immutable. What you can do though, is to use a fake double object that mimics the behavior of the original object, as described here.
For example, if you were running the same test outside of the browser (e.g. in NodeJS) you would do something like that
const chai = require('chai');
const sinon = require('sinon');
const SinonChai = require('sinon-chai');
chai.use(SinonChai);
chai.should();
context('test', function() {
it('should pass',
(done) => {
var cookieName = 'testCookieName';
document = {
cookie: cookieName + '=123'
};
var cookieValue = CookieHelper.GetCookie(cookieName);
console.log(cookieValue);
done();
});
});
in order to introduce a document object to the context and mimic it's cookies attribute by returning a fixed result.
Now, there is a workaround for the browser which involves redefining the getter and setter of 'document.cookie' as described here:
(function (document) {
var cookies = {};
document.__defineGetter__('cookie', function () {
var output = [];
for (var cookieName in cookies) {
output.push(cookieName + '=' + cookies[cookieName]);
}
return output.join(';');
});
document.__defineSetter__('cookie', function (s) {
var indexOfSeparator = s.indexOf('=');
var key = s.substr(0, indexOfSeparator);
var value = s.substring(indexOfSeparator + 1);
cookies[key] = value;
return key + '=' + value;
});
document.clearCookies = function () {
cookies = {};
};
})(document);
I am trying to do a simple IF statement to check if a specific Cookie exists:
I'm not looking to over complicate anything just something simple like
if (document.cookie.name("a") == -1 {
console.log("false");
else {
console.log("true");
}
What is this syntax for this?
first:
function getCookie(name) {
var cookies = '; ' + document.cookie;
var splitCookie = cookies.split('; ' + name + '=');
if (splitCookie.lenght == 2) return splitCookie.pop();
}
then you can use your if statement:
if (getCookie('a'))
console.log("false");
else
console.log("true");
should have work.
Maybe this can help (w3schools documentation about javascript cookies) :
https://www.w3schools.com/js/js_cookies.asp
At A Function to Get a Cookie
function getCookie(cname) {
var name = cname + "=";
var decodedCookie = decodeURIComponent(document.cookie);
var ca = decodedCookie.split(';');
for(var i = 0; i <ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') {
c = c.substring(1);
}
if (c.indexOf(name) == 0) {
return c.substring(name.length, c.length);
}
}
return "";
}
this could help you:
class Cookies {
static exists(name) {
return name && !!Cookies.get(name);
}
static set(name, value, expires = Date.now() + 8.64e+7, path = '/') {
document.cookie = `${name}=${value};expires=${expires};path=${path};`;
}
static get(name = null) {
const cookies = decodeURIComponent(document.cookie)
.split(/;\s?/)
.map(c => {
let [name, value] = c.split(/\s?=\s?/);
return {name, value};
})
;
return name
? cookies.filter(c => c.name === name).pop() || null
: cookies
;
}
}
I have two Angular services. The first creates a cookie and the second sets a URL to include the created cookie. I need the first to run before the second. Normally this is not an issue when using a service as my services tend to use a http call that has a success output, but in this instance, I don't have a success call and I don't know how I can trigger that the first is complete. Here is my code as it stands:
// Set Session Cookie
appCheckCookie.getCookie();
// Get Cart URL with Session Cookie
$scope.cartURL = appCartURL.getCartURL();
I have tried wrapping these in their own functions and trying to execute them in order, but that didn't work. and I tried something like this, but it didn't work:
appCheckCookie.getCookie(function(){
$scope.cartURL = appCartURL.getCartURL();
});
Here are my two services:
appServices.factory('appCheckCookie', ['$http', function ($http) {
var getCookie = function () {
// Create session cookie
function createCookie(name, value, days) {
if (days) {
var date = new Date();
date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
var expires = "; expires=" + date.toGMTString();
}
else var expires = "";
document.cookie = name + "=" + value + expires + "; path=/";
}
// Function to read cookie
function readCookie(name) {
var nameEQ = name + "=";
var ca = document.cookie.split(';');
for (var i = 0; i < ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') c = c.substring(1, c.length);
if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length, c.length);
}
return null;
}
var x = readCookie('ppkcookie')
if (x == null) {
// Get Session ID from backend URL
$http.post('/getSession', {}).success(function (data) {
// Create cookie from session ID from backend. Note that setting the days to 0 deletes the cookie on browser close (recommended)
createCookie('ppkcookie', data, 0);
console.log("Cookie Created: " + data);
}, function (err) {
console.log(err);
});
}
else {
var data = readCookie('ppkcookie');
console.log("Cookie Exists: " + data);
}
};
return {
getCookie: getCookie
};
}]),
appServices.factory('appCartURL', ['$http', function ($http) {
var getCartURL = function () {
// Function to read cookie
function readCookie(name) {
var nameEQ = name + "=";
var ca = document.cookie.split(';');
for (var i = 0; i < ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') c = c.substring(1, c.length);
if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length, c.length);
}
return null;
}
var x = readCookie('ppkcookie')
var baseCartURL = 'http://myecommsite.net/basket.html?Session_ID='
var cartURL = baseCartURL + x;
return cartURL;
};
return {
getCartURL: getCartURL
};
}]),
In case of handling Async operations, Promise should be one of the APIs to consider.
What is Promise?
This may give you some inspirations of how to use it in your case:
// Namespace YourService
function readCookie(name) {
return new Promise(function(resolve, reject){
var nameEQ = name + "=";
var ca = document.cookie.split(';');
for (var i = 0; i < ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') c = c.substring(1, c.length);
if (c.indexOf(nameEQ) == 0)
resolve(c.substring(nameEQ.length, c.length));
}
resolve(null); // consider reject(null)?
});
}
// Run in service
YourService.readCookie(name).then(function(cookieResponse) {
// Run your second service after cookie retrieved
}).catch(function(reason) {
// Catch reject
});
Another thing needs to be mentioned would be IE does not support Promise natively(Of course it doesn't..), so to use it in IE, you need to apply a polyfill.
Hope this can help.
Great advice on the use of $q. Along with a colleague, this is working since we only need the 1st service to signal that it is complete:
appServices.factory('appCheckCookie', ['$q', '$http', function ($q, $http) {
var getCookie = function () {
var deferred = $q.defer();
// Create session cookie
function createCookie(name, value, days) {
if (days) {
var date = new Date();
date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
var expires = "; expires=" + date.toGMTString();
}
else var expires = "";
document.cookie = name + "=" + value + expires + "; path=/";
}
// Function to read cookie
function readCookie(name) {
var nameEQ = name + "=";
var ca = document.cookie.split(';');
for (var i = 0; i < ca.length; i++) {
var c = ca[i];
while (c.charAt(0) == ' ') c = c.substring(1, c.length);
if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length, c.length);
}
return null;
}
var x = readCookie('ppkcookie')
if (x == null) {
// Get GUID for the cookie
$http.post('/getSession', {}).success(function (data) {
// Create cookie. Note that setting the days to 0 deletes the cookie on browser close (recommended)
createCookie('ppkcookie', data, 0);
console.log("Cookie Created: " + data);
deferred.resolve(data);
}, function (err) {
console.log(err);
});
}
else {
var cookieExists = readCookie('ppkcookie');
console.log("Cookie Exists: " + cookieExists);
deferred.resolve(cookieExists);
}
return deferred.promise;
};
return {
getCookie: getCookie
};
}]),
Then in the controller:
appCheckCookie.getCookie().then(function (data) {
// Get Cart URL
$scope.cartURL = appCartURL.getCartURL();
console.log($scope.cartURL);
});
What's a good way to check if a cookie exist?
Conditions:
Cookie exists if
cookie1=;cookie1=345534;
//or
cookie1=345534;cookie1=;
//or
cookie1=345534;
Cookie doesn't exist if
cookie=;
//or
<blank>
You can call the function getCookie with the name of the cookie you want, then check to see if it is = null.
function getCookie(name) {
var dc = document.cookie;
var prefix = name + "=";
var begin = dc.indexOf("; " + prefix);
if (begin == -1) {
begin = dc.indexOf(prefix);
if (begin != 0) return null;
}
else
{
begin += 2;
var end = document.cookie.indexOf(";", begin);
if (end == -1) {
end = dc.length;
}
}
// because unescape has been deprecated, replaced with decodeURI
//return unescape(dc.substring(begin + prefix.length, end));
return decodeURI(dc.substring(begin + prefix.length, end));
}
function doSomething() {
var myCookie = getCookie("MyCookie");
if (myCookie == null) {
// do cookie doesn't exist stuff;
}
else {
// do cookie exists stuff
}
}
I have crafted an alternative non-jQuery version:
document.cookie.match(/^(.*;)?\s*MyCookie\s*=\s*[^;]+(.*)?$/)
It only tests for cookie existence. A more complicated version can also return cookie value:
value_or_null = (document.cookie.match(/^(?:.*;)?\s*MyCookie\s*=\s*([^;]+)(?:.*)?$/)||[,null])[1]
Put your cookie name in in place of MyCookie.
document.cookie.indexOf('cookie_name=');
It will return -1 if that cookie does not exist.
p.s. Only drawback of it is (as mentioned in comments) that it will mistake if there is cookie set with such name: any_prefix_cookie_name
(Source)
This is an old question, but here's the approach I use ...
function getCookie(name) {
var match = document.cookie.match(RegExp('(?:^|;\\s*)' + name + '=([^;]*)'));
return match ? match[1] : null;
}
This returns null either when the cookie doesn't exist, or when it doesn't contain the requested name.
Otherwise, the value (of the requested name) is returned.
A cookie should never exist without a value -- because, in all fairness, what's the point of that? 😄
If it's no longer needed, it's best to just get rid of it all together.
function deleteCookie(name) {
document.cookie = name +"=; Path=/; Expires=Thu, 01 Jan 1970 00:00:01 GMT;";
}
ATTENTION!
the chosen answer contains a bug (Jac's answer).
if you have more than one cookie (very likely..) and the cookie you are retrieving is the first on the list, it doesn't set the variable "end" and therefore it will return the entire string of characters following the "cookieName=" within the document.cookie string!
here is a revised version of that function:
function getCookie( name ) {
var dc,
prefix,
begin,
end;
dc = document.cookie;
prefix = name + "=";
begin = dc.indexOf("; " + prefix);
end = dc.length; // default to end of the string
// found, and not in first position
if (begin !== -1) {
// exclude the "; "
begin += 2;
} else {
//see if cookie is in first position
begin = dc.indexOf(prefix);
// not found at all or found as a portion of another cookie name
if (begin === -1 || begin !== 0 ) return null;
}
// if we find a ";" somewhere after the prefix position then "end" is that position,
// otherwise it defaults to the end of the string
if (dc.indexOf(";", begin) !== -1) {
end = dc.indexOf(";", begin);
}
return decodeURI(dc.substring(begin + prefix.length, end) ).replace(/\"/g, '');
}
If you're using jQuery, you can use the jquery.cookie plugin.
Getting the value for a particular cookie is done as follows:
$.cookie('MyCookie'); // Returns the cookie value
regexObject.test( String ) is faster than string.match( RegExp ).
The MDN site describes the format for document.cookie, and has an example regex to grab a cookie (document.cookie.replace(/(?:(?:^|.*;\s*)test2\s*\=\s*([^;]*).*$)|^.*$/, "$1");). Based on that, I'd go for this:
/^(.*;)?\s*cookie1\s*=/.test(document.cookie);
The question seems to ask for a solution which returns false when the cookie is set, but empty. In that case:
/^(.*;)?\s*cookie1\s*=\s*[^;]/.test(document.cookie);
Tests
function cookieExists(input) {return /^(.*;)?\s*cookie1\s*=/.test(input);}
function cookieExistsAndNotBlank(input) {return /^(.*;)?\s*cookie1\s*=\s*[^;]/.test(input);}
var testCases = ['cookie1=;cookie1=345534;', 'cookie1=345534;cookie1=;', 'cookie1=345534;', ' cookie1 = 345534; ', 'cookie1=;', 'cookie123=345534;', 'cookie=345534;', ''];
console.table(testCases.map(function(s){return {'Test String': s, 'cookieExists': cookieExists(s), 'cookieExistsAndNotBlank': cookieExistsAndNotBlank(s)}}));
Note that if a cookie is secure, you cannot check in client side for its existence using document.cookie (which all of the answers are using). Such cookie can be checked only at sever side.
instead of the cookie variable you would just use document.cookie.split...
var cookie = 'cookie1=s; cookie1=; cookie2=test';
var cookies = cookie.split('; ');
cookies.forEach(function(c){
if(c.match(/cookie1=.+/))
console.log(true);
});
There are several good answers here. I however prefer [1] not using a regular expression, and [2] using logic that is simple to read, and [3] to have a short function that [4] does not return true if the name is a substring of another cookie name . Lastly [5] we can't use a for each loop since a return doesn't break it.
function cookieExists(name) {
var cks = document.cookie.split(';');
for(i = 0; i < cks.length; i++)
if (cks[i].split('=')[0].trim() == name) return true;
}
function getCookie(name) {
var dc = document.cookie;
var prefix = name + "=";
var begin = dc.indexOf("; " + prefix);
if (begin == -1) {
begin = dc.indexOf(prefix);
if (begin != 0) return null;
else{
var oneCookie = dc.indexOf(';', begin);
if(oneCookie == -1){
var end = dc.length;
}else{
var end = oneCookie;
}
return dc.substring(begin, end).replace(prefix,'');
}
}
else
{
begin += 2;
var end = document.cookie.indexOf(";", begin);
if (end == -1) {
end = dc.length;
}
var fixed = dc.substring(begin, end).replace(prefix,'');
}
// return decodeURI(dc.substring(begin + prefix.length, end));
return fixed;
}
Tried #jac function, got some trouble, here's how I edited his function.
For anyone using Node, I found a nice and simple solution with ES6 imports and the cookie module!
First install the cookie module (and save as a dependency):
npm install --save cookie
Then import and use:
import cookie from 'cookie';
let parsed = cookie.parse(document.cookie);
if('cookie1' in parsed)
console.log(parsed.cookie1);
Using Javascript:
function getCookie(name) {
let matches = document.cookie.match(new RegExp(
"(?:^|; )" + name.replace(/([\.$?*|{}\(\)\[\]\\\/\+^])/g, '\\$1') + "=([^;]*)"
));
return matches ? decodeURIComponent(matches[1]) : undefined;
}
Parse cookies with Array.prototype.reduce() into an object (ES6)
const cookies = document.cookie.split(";").reduce((e, t) => {
const [c, n] = t.trim().split("=").map(decodeURIComponent);
try { // this can be removed if you do not need JSON cookies parsed
return Object.assign(e, {
[c]: JSON.parse(n)
})
}
catch (t) {
return Object.assign(e, {
[c]: n
})
}
}, {})
Check if your cookie is there
typeof cookies.yourCookie === "string";
If anyone is still looking into this post maybe this will help.
First do a function to get the cookie, something like this..
function getCookie(cname) {
let name = cname + "=";
let ca = document.cookie.split(';');
for(let i = 0; i < ca.length; i++) {
let c = ca[i];
while (c.charAt(0) == ' ') {
c = c.substring(1);
}
if (c.indexOf(name) == 0) {
return c.substring(name.length, c.length);
}
}
return "";
}
Then you could check if the specific cookie exists before doing something else
if( getCookie(mycookieName)){
// do something....
}
// check if cookie is present
function is_CookiePresent( cookieName ){
if( void 0 != cookieName && "" != cookieName && null != cookieName ){
var is_present = document.cookie.split(";").filter(e=>{
if(e.trim().split("=").includes(cookieName)) return true;
})
if(!is_present.length){return false;}
return true;
}
else{
return false;
}
}
// Get cookie name value :)
function getCookieValue( cookieName ){
if( void 0 != cookieName && "" != cookieName && null != cookieName ){
var is_present = document.cookie.split(";").filter(e=>{
if(e.trim().split("=").includes(cookieName)) return true;
})
if(!is_present.length){return false;}
var __CookieValue = is_present.join('').trim();
return __CookieValue.substring(__CookieValue.indexOf('=')+1);
}
else{
return false;
}
}
use this method instead:
function getCookie(name) {
var value = "; " + document.cookie;
var parts = value.split("; " + name + "=");
if (parts.length == 2) return parts.pop().split(";").shift();
else return null;
}
function doSomething() {
var myCookie = getCookie("MyCookie");
if (myCookie == null) {
// do cookie doesn't exist stuff;
}
else {
// do cookie exists stuff
}
}
/// ************************************************ cookie_exists
/// global entry point, export to global namespace
/// <synopsis>
/// cookie_exists ( name );
///
/// <summary>
/// determines if a cookie with name exists
///
/// <param name="name">
/// string containing the name of the cookie to test for
// existence
///
/// <returns>
/// true, if the cookie exists; otherwise, false
///
/// <example>
/// if ( cookie_exists ( name ) );
/// {
/// // do something with the existing cookie
/// }
/// else
/// {
/// // cookies does not exist, do something else
/// }
function cookie_exists ( name )
{
var exists = false;
if ( document.cookie )
{
if ( document.cookie.length > 0 )
{
// trim name
if ( ( name = name.replace ( /^\s*/, "" ).length > 0 ) )
{
var cookies = document.cookie.split ( ";" );
var name_with_equal = name + "=";
for ( var i = 0; ( i < cookies.length ); i++ )
{
// trim cookie
var cookie = cookies [ i ].replace ( /^\s*/, "" );
if ( cookie.indexOf ( name_with_equal ) === 0 )
{
exists = true;
break;
}
}
}
}
}
return ( exists );
} // cookie_exists
function getcookie(name = '') {
let cookies = document.cookie;
let cookiestore = {};
cookies = cookies.split(";");
if (cookies[0] == "" && cookies[0][0] == undefined) {
return undefined;
}
cookies.forEach(function(cookie) {
cookie = cookie.split(/=(.+)/);
if (cookie[0].substr(0, 1) == ' ') {
cookie[0] = cookie[0].substr(1);
}
cookiestore[cookie[0]] = cookie[1];
});
return (name !== '' ? cookiestore[name] : cookiestore);
}
To get a object of cookies simply call getCookie()
To check if a cookie exists, do it like this:
if (!getcookie('myCookie')) {
console.log('myCookie does not exist.');
} else {
console.log('myCookie value is ' + getcookie('myCookie'));
}
Or just use a ternary operator.
function hasCookie(cookieName){
return document.cookie.split(';')
.map(entry => entry.split('='))
.some(([name, value]) => (name.trim() === cookieName) && !!value);
}
Note: The author wanted the function to return false if the cookie is empty i.e. cookie=; this is achieved with the && !!value condition. Remove it if you consider an empty cookie is still an existing cookie…
var cookie = 'cookie1=s; cookie1=; cookie2=test';
var cookies = cookie.split('; ');
cookies.forEach(function(c){
if(c.match(/cookie1=.+/))
console.log(true);
});
You can verify if a cookie exists and it has a defined value:
function getCookie(cookiename) {
if (typeof(cookiename) == 'string' && cookiename != '') {
const COOKIES = document.cookie.split(';');
for (i = 0; i < COOKIES.length; i++) {
if (COOKIES[i].trim().startsWith(cookiename)) {
return COOKIES[i].split('=')[1];
}
}
}
return null;
}
const COOKIE_EXAMPLE = getCookie('example');
if (COOKIE_EXAMPLE == 'stackoverflow') { ... }
// If is set a cookie named "example" with value "stackoverflow"
if (COOKIE_EXAMPLE != null) { ... }
// If is set a cookie named "example" ignoring the value
It will return null if cookie doesn't exists.