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The length read-only property of the Storage interface returns an integer representing the number of data items stored in the Storage object.

Syntax

var aLength = storage.length;

Return value

An integer.

Example

The following function adds three data items to the local storage for the current domain, then returns the number of items in the storage:

function populateStorage() {
  localStorage.setItem('bgcolor', 'yellow');
  localStorage.setItem('font', 'Helvetica');
  localStorage.setItem('image', 'cats.png');

  localStorage.length; // should return 3
}

Note: For a real world example, see our Web Storage Demo.

Specifications

Specification Status Comment
WHATWG HTML Living Standard
The definition of 'Storage.length' in that specification.
Living Standard  

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
localStorage 4 (Yes) 3.5 8 10.50 4
sessionStorage 5 ? 2 8 10.50 4
Feature Android Edge Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support 2.1 (Yes) ? 8 11 iOS 3.2

All browsers have varying capacity levels for both localStorage and sessionStorage. Here is a detailed rundown of all the storage capacities for various browsers.

Note: since iOS 5.1, Safari Mobile stores localStorage data in the cache folder, which is subject to occasional clean up, at the behest of the OS, typically if space is short.

See also

Using the Web Storage API

Document Tags and Contributors

 Contributors to this page: fscholz, chrisdavidmills, abbycar, teoli
 Last updated by: fscholz,