What Are Cookies And How Do I Use Them – JavaScript


  • Cookies are pieces of information exchanged between the server and the client.
  • It saves the user’s information on websites; in other words, it is a piece of data stored on the computer.

The following items are included in this blog:

  1. Why do we require them?
  2. How to make/use them
  3. There are five variable fields.
  4. What does javascript do with cookies?
  5. An example of how to apply them

Why do we require cookies?

  • The HTTP protocol is used to communicate between a web browser and a server. However, after transmitting the information to the browser, the server never keeps it.
  • The information may be needed in the future for some vital purpose.

Here how do cookies come??

  • When we employ cookies, the browser does not have to contact with the servers every time it requires information.
  • Instead, cookies are used to save information on the user’s computer so that it may be accessed from there.


  • With the assistance of a document.cookie feature Javascript has the ability to read, write, and create cookies.
    What is the syntax for making a cookie?

document.cookie = “name=xyz”;

5 fields with variable values
Based on a list of 5 changeable fields, each cookie can contain 5 variable path names or domains to a specific website.

The mentioned variable fields are listed below.

  •  Expires → It shows the date cookie will expire. If it is blank, whenever the user will visit the page it will be expired
  • Domain → It displays the domain name of the site.
  • Path → The path to the directory or web page that set the cookie. This may be blank if you want to retrieve the cookie from any directory or page.
  • Secure → If this field contains the word “secure”, then the cookie may only be retrieved with a secure server. If this field is blank, no such restriction exists.
  • Name=Value → Cookies are set and retrieved in the form of key-value pairs

What can javascript do with cookies?
Javascript can do a variety of things with cookies. Among them are:

  • It is capable of reading cookies.
  • It is capable of updating a cookie.
  • It has the ability to remove cookies.
  • It has the ability to check the cookie.

Let’s look at some examples of how we may write a javascript function to check the cookie.

function checkCookies(){
  let cookie = getCookie("emp");
  if(cookie != ""){
    alert("cookie is "+cookie);
    cookie=prompt("can you enter your name?"); 
    if(cookie != "" && cookie!=null){
      setCookies("emp", cookie, 2);



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