Page 156 - CITS - Computer Software Application -TT

COMPUTER SOFTWARE APPLICATION - CITS

document.cookie = “username=John Doe”;
You can also add an expiry date (in UTC time). By default, the cookie is deleted when the browser is closed:
document.cookie = “username=John Doe; expires=Thu, 18 Dec 2013 12:00:00 UTC”;
With a path parameter, you can tell the browser what path the cookie belongs to. By default, the cookie belongs
to the current page.
document.cookie = “username=John Doe; expires=Thu, 18 Dec 2013 12:00:00 UTC; path=/”;
Read a Cookie with JavaScript
With JavaScript, cookies can be read like this:
let x = document.cookie;

document.cookie will return all cookies in one string much like: cookie1=value; cookie2=value; cookie3=value;
Change a Cookie with JavaScript
With JavaScript, you can change a cookie the same way as you create it:
document.cookie = “username=John Smith; expires=Thu, 18 Dec 2013 12:00:00 UTC; path=/”;

The old cookie is overwritten.
Delete a Cookie with JavaScript
Deleting a cookie is very simple.
You don’t have to specify a cookie value when you delete a cookie.
Just set the expires parameter to a past date:
document.cookie = “username=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/;”;

You should define the cookie path to ensure that you delete the right cookie.
Some browsers will not let you delete a cookie if you don’t specify the path.
The Cookie String
The document.cookie property looks like a normal text string. But it is not.

Even if you write a whole cookie string to document.cookie, when you read it out again, you can only see the
name-value pair of it.
If you set a new cookie, older cookies are not overwritten. The new cookie is added to document.cookie, so if you
read document.cookie again you will get something like:
cookie1 = value; cookie2 = value;
Display All Cookies Create Cookie 1 Create Cookie 2 Delete Cookie 1 Delete Cookie 2
If you want to find the value of one specified cookie, you must write a JavaScript function that searches for the
cookie value in the cookie string.
JavaScript Cookie Example
In the example to follow, we will create a cookie that stores the name of a visitor.

The first time a visitor arrives to the web page, he/she will be asked to fill in his/her name. The name is then stored
in a cookie.
The next time the visitor arrives at the same page, he/she will get a welcome message.

For the example we will create 3 JavaScript functions:
1 A function to set a cookie value
2 A function to get a cookie value
3 A function to check a cookie value

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CITS : IT&ITES - Computer Software Application - Lesson 37 - 46