How Cookies, sessionStorage and localStorage works in JavaScript ?

In this article we are take care of what is cookies, sessionStorage and localStorage ? How we can perform create, read and delete operation on cookies, sessionStorage and localStorage ?

1. Cookies

Cookies is a text file stored on the local computer and it is use for tracking purpose. When client send request to server, server generate response/information client can save that response/information in cookies. It helps clients for future use. (Here client is browser.) Maximum size of cookies file is 4KB.

Create / Read / Edit / Delete cookies

We can create cookies with the document.cookie property.

document.cookie = "personName=Sagar Behare";

The cookie is deleted when browser is closed, but we can add expiry date also.

document.cookie = "personName=Sagar Behare expires=SUN, 30 Aug 2020 12:00:00 UTC";

By default, the cookie belongs to the current page but we can mention the path of the cookies.

document.cookie = "username=Sagar Behare; expires=SUN, 30 Aug 2020 12:00:00 UTC; path=/;";

We can read cookie in following ways.

var readVal = document.cookie;

We can edit or override cookies in same way that we create.

document.cookie = "username=Sagar Behare; expires=SUN, 30 Aug 2020 12:00:00 UTC; path=/;";

Deletion of cookies is very simple, just don’t mention the value.

document.cookie = "username=; expires=SUN, 30 Aug 2020 12:00:00 UTC; path=/;";

2. SessionStorage

The sessionStorage store the data only for one session. If we close the tab/browser session is closed. We can save the values in sessionStorage in terms of key-value.

Create / Read / Delete sessionStorage

Save data in sessionStorage

sessionStorage.setItem("personName", "Sagar Behare");

Read data from sessionStorage

var personName = sessionStorage.getItem("personName");

Remove data from sessionStorage


Remove all data from sessionStorage


3. LocalStorage

The localStorage store the data permanently without any expiry. We lost data only case of delete cache of browser.

Create / Read / Delete localStorage

Save data in localStorage

localStorage.setItem("personName", "Sagar Behare");

Read data from localStorage

var personName = localStorage.getItem("personName");

Remove data from localStorage


Remove all data from localStorage


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