Represents the local storage area. Items in local storage are local to the machine the add-on was installed on.
When the add-on is uninstalled, its associated local storage is cleared (note that in Firefox, this is only true from version 51 onwards).
Also in Firefox, you can prevent the browser from clearing local storage on uninstall by visiting "about:config" and setting the following two browser preferences to true: "keepUuidOnUninstall" and "keepStorageOnUninstall". This feature is provided to help developers test their add-on. WebExtensions themselves are not able to change these preferences.
Methods
The local object implements the methods defined on the storage.StorageArea type:
storage.StorageArea.get()- Retrieves one or more items from the storage area.
storage.StorageArea.getBytesInUse()- Gets the amount of storage space (in bytes) used one or more items being stored in the storage area.
storage.StorageArea.set()- Stores one or more items in the storage area. If the item already exists, its value will be updated. When you set a value, the
storage.onChangedevent will fire. storage.StorageArea.remove()- Removes one or more items from the storage area.
storage.StorageArea.clear()- Removes all items from the storage area.
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
| Chrome | Edge | Firefox | Firefox for Android | Opera | |
|---|---|---|---|---|---|
| Basic support | Yes | Yes | 45.0 | 48.0 | 33 |
Compatibility notes
Firefox
- The storage API is supported in content scripts from version 48.
This API is based on Chromium's chrome.storage API. This documentation is derived from storage.json in the Chromium code.
Microsoft Edge compatibility data is supplied by Microsoft Corporation and is included here under the Creative Commons Attribution 3.0 United States License.
// Copyright 2015 The Chromium Authors. All rights reserved. // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following disclaimer // in the documentation and/or other materials provided with the // distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived from // this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.