Web/API/Storage/setItem

The setItem() method of the Storage interface, when passed a key name and value, will add that key to the given Storage object, or update that key's value if it already exists.

Syntax

storage.setItem(keyName, keyValue);

Parameters

keyName: A DOMString containing the name of the key you want to create/update.
keyValue: A DOMString containing the value you want to give the key you are creating/updating.

Return value

undefined.

Exceptions

setItem() may throw an exception if the storage is full. Particularly, in Mobile Safari (since iOS 5) it always throws when the user enters private mode. (Safari sets the quota to 0 bytes in private mode, unlike other browsers, which allow storage in private mode using separate data containers.) Hence developers should make sure to always catch possible exceptions from setItem().

Example

The following function creates three data items inside local storage.

function populateStorage() {
  localStorage.setItem('bgcolor', 'red');
  localStorage.setItem('font', 'Helvetica');
  localStorage.setItem('image', 'myCat.png');
}

Note: To see this used within a real world example, see our [[../../../../../../../mdn.github.io/dom-examples/web-storage/index|Web Storage Demo]].

Specifications

Specification	Status	Comment
HTML Living StandardThe definition of 'Storage.setItem' in that specification.	Living Standard

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`setItem`	Chrome Full support 4	Edge Full support 12	Firefox Full support 3.5	IE Full support 8	Opera Full support 10.5	Safari Full support 4	WebView Android Full support ≤37	Chrome Android Full support 18	Firefox Android Full support 6	Opera Android Full support 11	Safari iOS Full support 3.2	Samsung Internet Android Full support 1.0

Legend

Full support: Full support