Storage

`sessionStorage.setItem`

Adds a key/value pair to the sessionStorage object for the duration of the page session

Syntax

JavaScript

sessionStorage.setItem(key, value)

Parameters

Parameter	Type	Description
key	string	The name of the key
value	string	The value to store

Return Value

undefined

Examples

Basic Usage

sessionStorage.setItem('currentStep', '3')
console.log(sessionStorage.getItem('currentStep')) // '3'

Practical Example

function saveFormDraft(formId: string, data: Record<string, string>) {
  sessionStorage.setItem(`draft_${formId}`, JSON.stringify(data))
}

Advanced Usage

sessionStorage.setItem('sessionStart', new Date().toISOString())
console.log('Session started at:', sessionStorage.getItem('sessionStart'))

Understanding sessionStorage.setItem

The sessionStorage.setItem method in JavaScript adds a key/value pair to the sessionStorage object for the duration of the page session. It belongs to the Storage object and is one of the most widely used methods for working with storage values in modern JavaScript and TypeScript applications.

The method signature is sessionStorage.setItem(key, value). It accepts 2 parameters: key, value. When called, it returns undefined. Understanding when and how to use setItem() helps you write more expressive, readable code.

Common use cases for sessionStorage.setItem include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like sessionstorage-getitem, sessionstorage-removeitem, localstorage-setitem, enabling you to chain operations together for complex data manipulation pipelines.

Browser support for sessionStorage.setItem is excellent across all modern browsers including Chrome, Firefox, Safari, and Edge. It is also fully supported in Node.js and Deno. For older environments, transpilation with Babel or a polyfill may be needed.