Storage.length

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
Web Storage The definition of 'length' in that specification.	Recommendation

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
localStorage	4	3.5	8	10.50	4
sessionStorage	5	2	8	10.50	4

Feature	Android	Firefox Mobile (Gecko)	IE Phone	Opera Mobile	Safari Mobile
Basic support	2.1	?	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.