Client Side Scripting language Unit 4 Notes.

Chapter 4
Cookies and Browser Data

,Cookie:..
• Cookies are data, stored in small text files, on your computer.
• When a web server has sent a web page to a browser, the
connection is shut down, and the server forgets everything
about the user.
• Cookies were invented to solve the problem "how to
remember information about the user":
• When a user visits a web page, his/her name can be stored in
a cookie.
• Next time the user visits the page, the cookie "remembers"
his/her name.
• Cookies are saved in name-value pairs like:
username = AAA

,Cookie Cont.:
• When a browser requests a web page from a server,
cookies belonging to the page are added to the
request.
• This way the server gets the necessary data to
"remember" information about users.
• None of the examples below will work if your
browser has local cookies support turned off.

, Creating Cookie :
• JavaScript can create, read, and delete cookies with
the document.cookie property.
• With JavaScript, a cookie can be created like this:
document.cookie = "username=AAA";
• You can also add an expiry date (in UTC time). By
default, the cookie is deleted when the browser is closed:
document.cookie = "username=AAA; 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=/";