Can Greasemonkey delete cookies from a given domain? If so, how?
There are major limitations on what Greasemonkey can delete. Other tools may be better for what you want, see below. But, if all of these conditions are met:
The cookies you want to delete are on the current page's domain.
They are not "Secure cookies".
You loop through the possible paths, including /, a blank path, etc.
No cookies are set by javascript, after the page loads.
The thing tracking you really is a "cookie". Many websites use a variety of other techniques, including LSO's, local storage, etc.
THEN, the following code will delete them:
//--- Loop through cookies and delete them.
var cookieList = document.cookie.split (/;\s*/);
for (var J = cookieList.length - 1; J >= 0; --J) {
var cookieName = cookieList[J].replace (/\s*(\w+)=.+$/, "$1");
eraseCookie (cookieName);
}
Where eraseCookie() is:
(Note that this eraseCookie gets many more cookies by attempting all possible paths and the most likely sub-domains.)
function eraseCookie (cookieName) {
//--- ONE-TIME INITS:
//--- Set possible domains. Omits some rare edge cases.?.
var domain = document.domain;
var domain2 = document.domain.replace (/^www\./, "");
var domain3 = document.domain.replace (/^(\w+\.)+?(\w+\.\w+)$/, "$2");;
//--- Get possible paths for the current page:
var pathNodes = location.pathname.split ("/").map ( function (pathWord) {
return '/' + pathWord;
} );
var cookPaths = [""].concat (pathNodes.map ( function (pathNode) {
if (this.pathStr) {
this.pathStr += pathNode;
}
else {
this.pathStr = "; path=";
return (this.pathStr + pathNode);
}
return (this.pathStr);
} ) );
( eraseCookie = function (cookieName) {
//--- For each path, attempt to delete the cookie.
cookPaths.forEach ( function (pathStr) {
//--- To delete a cookie, set its expiration date to a past value.
var diagStr = cookieName + "=" + pathStr + "; expires=Thu, 01-Jan-1970 00:00:01 GMT;";
document.cookie = diagStr;
document.cookie = cookieName + "=" + pathStr + "; domain=" + domain + "; expires=Thu, 01-Jan-1970 00:00:01 GMT;";
document.cookie = cookieName + "=" + pathStr + "; domain=" + domain2 + "; expires=Thu, 01-Jan-1970 00:00:01 GMT;";
document.cookie = cookieName + "=" + pathStr + "; domain=" + domain3 + "; expires=Thu, 01-Jan-1970 00:00:01 GMT;";
} );
} ) (cookieName);
}
Optional function, for information or debug:
function listCookies () {
var cookieList = document.cookie.split (/;\s*/);
for (var J = 0, numCookies = cookieList.length; J < numCookies; ++J) {
console.log ("Cookie ", J, ": ", cookieList[J]);
}
}
Your GM script can also use iFrame tricks to delete cookies on third-party domains, but GM is not the best way to handle cookies, in general.
Don't be fooled by any other claims, Greasemonkey and javascript simply cannot delete a cookie unless all of the conditions, listed at the top of this answer, are met. Note that javascript and Greasemonkey cannot even see all the cookies on a page.
Greasemonkey is not the best tool for this, although it may be adequate for select situations.
Here are some far more powerful solutions:
Use Selective Cookie Delete. It keeps the cookies you want and deletes the rest. It does this at the push of a very handy button or automatically when Firefox closes. Both white-lists and black-lists are supported.
Use BetterPrivacy for sneakier LSO's.
Run CCleaner at least once a week, to exorcise a broad spectrum of tracking and cruft.
For powerful, custom, fully-automated cookie removal that does not have the severe limitations that Greasemonkey has, and that runs more often than Selective Cookie Delete, you can write your own browser extension.
You should be able to delete cookies for the currently open site. Have a look at the Cookie Zapper script, this may do what you want and if not the source will probably point you in the right direction.
Related
I've already made the animation functions, but I don't want it to animate every time the same person visits the site. So the plan is to check for the cookie and if it is there, skip the intro animation, but if it's not, I want to run the intro animation and create the cookie. I don't know a lot about cookies or Js, so I'm kind of stuck.
This is what I'm using for many projects.
/*-----------------------------------------------------
global function for Set/Get Cookie
------------------------------------------------------*/
function setCookie(cname,cvalue,exdays) {
var d = new Date();
d.setTime(d.getTime() + (exdays*24*60*60*1000));
var expires = "expires=" + d.toGMTString();
document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}
function getCookie(name) {
var value = "; " + document.cookie;
var parts = value.split("; " + name + "=");
if (parts.length == 2) return parts.pop().split(";").shift();
}
then set/get like:
SET:
setCookie("c2u", c2u, 365); NOTE: 365 is 365 day
GET:
var cookieSelTimeZone = getCookie("selectedTimeZone");
JavaScript can create, read, and delete cookies with the document.cookie property. U can use any name/key you want like u use in PHP.
You can then read from the cookie property to see if your key/value is set.
More info can be found here
I'm trying to create a simple notepad app (basic CRUD) using just JavaScript and it has to have a login/signup function, I've managed to create code to get a cookie, if the cookie doesn't exist it sets one and then deletes one after an expiry date.
Here is my cookie code:
function getCookie(usersCookie){
if (document.cookie.length > 0){
begin = document.cookie.indexOf(usersCookie+"=")
if (begin != -1){
begin += usersCookie.length+1;
end = document.cookie.indexOf(";", begin);
if (end == -1) end = document.cookie.length;
return unescape(document.cookie.substring(begin, end));
}
}
}
function setCookie(usersCookie, value, expiredays){
var ExpireDate = new Date ();
ExpireDate.setTime(ExpireDate.getTime() + (expiredays * 24 * 3600 * 1000));
document.cookie = usersCookie + "=" + escape(value) + ((expiredays == null) ? "" : "; expires =" + ExpireDate.toGMTString());
}
function delCookie (usersCookie){
if (getCookie(usersCookie)){
document.cookie = usersCookie + "=" + "; expires=Thu, 14-Jan-15 00:00:01 GMT";
}
}
What I need to know now is how I save arrays to the cookie to access later since I can use this for the rest of the app, I'm replacing the DB with Cookies, I'm aware this is the worst way to do something like this, this is purely a self learning exercise to get used to using cookies.
Thanks in advance
you can use JSON.stringify
var arr = [1,2,3,4];
var output = JSON.stringify(arr)
outputs
"[1,2,3,4]"
save this value in cookie and while fetching back use JSON.parse
arr = JSON.parse( output );
I am new to JavaScript and cookies, so I have this weird question as different websites had different format. So I had confusion on how the cookies read and access the different parts of it, i.e. how do cookies recognize names from path or expiration date? Do we always have to specify "username=...;path=/;" for it to recognize it or does it automatically find it based on the format?
And the main question that I am trying to figure is how I can add a value to the cookie creation code, such as a " document.cookie="username=John;visit=1;" and use that visit part to tell the hit count by adding 1 to it every time the page loads.
Thank you!
I use two functions (maybe the original code was from here or here) for getting and setting cookies, here are they:
function setCookie(cookieName, content, expires, path) {
var date = new Date();
date.setDate(date.getDate() + expires);
var cookie = escape(content) + (expires == null ? "" : "; expires=" + date.toUTCString()) + (path != null ? "; path=" + path : "");
document.cookie = cookieName + "=" + cookie;
return true;
}
function getCookie(cookieName) {
var cookie = document.cookie,
begin = cookie.indexOf(" " + cookieName + "=");
if (begin == -1) begin = cookie.indexOf(cookieName + "=");
if (begin == -1) cookie = null;
else {
begin = cookie.indexOf("=", begin) + 1;
var end = cookie.indexOf(";", begin);
if (end == -1) end = cookie.length;
cookie = unescape(cookie.substring(begin, end));
}
return cookie;
}
With them you can easily do what you want:
Handle the page loads (eg <body onload="pageLoad()">)
Add a script element to the head part of the page, and the two funtions above
Add the following function inside the script element:
function pageLoad() {
var cCont = getCookie('hitCount');
var count = 0;
if (cCont != null) count = parseInt(count + '');
setCookie('hitCount', (count + 1) + '', null, null);
}
If you want to get the hit count, you can use the count variable, or use the getCookie function again.
Your first question is not totally clear to me, but read this page, there are nice examples and code samples. This is another good presentation of cookies.
We are trying to clear the cookie details in browser on pressing 'Logout' button with the following code, but the script doesn't remove the session cookie from the browser. But by clearing the session cookies in IE8 browser using developer tool(Tools > Developer Tools >Cache > Clear Session Cookies), the cookies are cleared.
<html:link page="/home.do" onclick="logout();">
<html:img page="/images/logout.jpg"/>
</html:link>
function logout(){
var cookies = document.cookie.split(";");
for (var i = 0; i < cookies.length; i++) {
var cookiename = cookies[i].split("=");
var d = new Date();
d.setDate(d.getDate() - 4);
var expires = ";expires="+d;
var value="";
document.cookie = cookiename + "=" + value + expires + ";";
}
}
How to clear the Session cookies from the browser using script?
if it is httpOnly, then you can not delete it, try modify it from server side
from javascript: Not specifying expiring field, also set value to null, and if it is also hostonly, not specifying domain
If it is a 'session' variable you want to clear...
unset( $_SESSION['YOUR_SESSION_VARIABLE_NAME'] );
This will completely remove this session variable. The title is misleading. The code he shows is not 'session' cookies, they are regular 'cookies'.
I am using Javascript to set the cookie and read the value from cookie.I am using the code available at http://www.w3schools.com/js/js_cookies.asp for creating and reading the value of cookie.when the page loads i am checking that whether that cookie exists or not .Every thing is working fine except it is not reading the cookie when i set it first time and try to read in next page load .it is setting the cookie but does not read only first time .
Here is my code :-
function setCookie(c_name, value, exdays) {
var exdate = new Date();
exdate.setDate(exdate.getDate() + exdays);
var c_value = escape(value) + ((exdays == null) ? "" : "; expires=" + exdate.toUTCString());
document.cookie = c_name + "=" + c_value;
}
//To get the cookie:-
function getCookie(c_name) {
var i, x, y, ARRcookies = document.cookie.split(";");
for (i = 0; i < ARRcookies.length; i++) {
x = ARRcookies[i].substr(0, ARRcookies[i].indexOf("="));
y = ARRcookies[i].substr(ARRcookies[i].indexOf("=") + 1);
x = x.replace(/^\s+|\s+$/g, "");
if (x == c_name) {
return unescape(y);
}
}
}
//to Delete the cookie:-
function cookieDelete(c_name) {
setCookie(c_name, "delete", -1);
}
And on page load i am using it like :-
$(document).ready(function () {
var aZ = getCookie("menuSave");
if (aZ) {
//do Some thing here
}
else {
setCookie("menuSave", "mysp", null);
}
});
You need to add a 'path' to your cookie. For example:
document.cookie = 'ppkcookie2=yet another test; expires=Fri, 27 Jul 2001 02:47:11 UTC; path=/';
The path represents the relative path in your website which the cookie will be readable.
path=/ means it'll be readable on your whole website.
path=/common/ means it'll be readable only in /common/ folder (and its subfolders)
This might not be the answer to your problem but yet a alternative easier solution, hope it helps!
save menu
localStorage.setItem("menusave","vale");
load value
localStorage.getItem("menusave");
Just trying to help!
Since you have marked the question as asp.net,
You can set the cookies as follows:
HttpCookie aCookie = new HttpCookie("lastVisit");
aCookie.Value = DateTime.Now.ToString();
aCookie.Expires = DateTime.Now.AddDays(1);
Response.Cookies.Add(aCookie);
And read it back like:
if(Request.Cookies["lastVisit"] != null)
Label1.Text = Server.HtmlEncode(Request.Cookies["lastVisit"].Value);
Refer MSDN Cookies overview
When you pass null for the expiration days it makes your cookie into a session cookie that will not persist very long.
Change this:
setCookie("menuSave", "mysp", null);
to this to give it an actual expiration date:
setCookie("menuSave", "mysp", 7);
If you want to retrieve the cookie from any page besides the exact same page that set it, you will also need to set a path value in the cookie that allows the cookie to be retrieved on more than just the exact page that set it.