JavaScript SessionStorage Object API Guide

In this guide, we will learn all the JavaScript sessionStorage object APIs/methods with an example.

The sessionStorage object stores data for only one session (the data is deleted when the browser tab is closed).

In this guide, we will learn below all 5 sessionStorage object methods with example.

JavaScript  SessionStorage APIs/Methods

To use SessionStorage in your web applications, there are 5 methods to choose from:

1. setItem(): Add key and value to SessionStorage
2. getItem(): Retrieve a value by the key from SessionStorage
3. removeItem(): Remove an item by key from SessionStorage
4. clear(): Clear all SessionStorage
5. key(): Passed a number to retrieve nth key of a SessionStorage

Syntax

window.sessionStorage

The syntax for SAVING data to sessionStorage:

sessionStorage.setItem("key", "value");

The syntax for READING data from sessionStorage:

var lastname = sessionStorage.getItem("key");

The syntax for REMOVING saved data from sessionStorage:

sessionStorage.removeItem("key");

The syntax for REMOVING ALL saved data from sessionStorage:

sessionStorage.clear();

Syntax for Key() Method:

var KeyName = sessionStorage.key(index);

Let's demonstrate each method of SessionStorage with example.

SessionStorage.setItem() API/Method

This method just as the name implies allows you to store values in the sessionStorage object.

It takes two parameters, a key and a value. The key can be referenced later to fetch the value attached to it.

sessionStorage.setItem("firstName", "Ramesh");

Where "firstName" is the key and "Ramesh" is the value. Also, note that unlike LocalStorage, the sessionStoragecan only store strings.

To store arrays or objects you would have to convert them to strings.

To do this we use the JSON.stringify() method before passing to setItem() .

var user = {
 firstName : "Ramesh",
 lastName : "Fadatare"
}
sessionStorage.setItem("id", JSON.stringify(user));

Note that the data is deleted when the browser tab is closed.

sessionStorage.getItem() API/Method

The getItem() method allows you to access the data stored in the browser’s sessionStorage object.

It accepts only one parameter which is the key and returns the value as a string.

To retrieve the user object from the key stored above:

sessionStorage.getItem('id');

This returns a string with value as;

"{"firstName":"Ramesh","lastName":"Fadatare"}"

To use this value, you would have to convert it back to an object using JSON.parse() method.

JSON.parse(sessionStorage.getItem('id'));

sessionStorage.removeItem() API/Method

Let's use the removeItem() method to remove the item from the key. Let's remove the user object previously stored using setItem() method:

sessionStorage.removeItem('id');

sessionStorage.clear() API/Method

This method, when invoked clears the entire storage of all records for that domain. It does not receive any parameters.

sessionStorage.clear();

sessionStorage.key() API/Method

The key() method comes in handy in situations where you need to loop through keys and allows you to pass a number or index to local storage to retrieve the name of the key.

var KeyName = sessionStorage.key(index);

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