Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://developer.chrome.com/docs/extensions/reference/api/storage below:

chrome.storage | API | Chrome for Developers

Stay organized with collections Save and categorize content based on your preferences.

Use the chrome.storage API to store, retrieve, and track changes to user data.

storage

To use the storage API, declare the "storage" permission in the extension manifest. For example:

{
  "name": "My extension",
  ...
  "permissions": [
    "storage"
  ],
  ...
}

The Storage API provides an extension-specific way to persist user data and state. It's similar to the web platform's storage APIs (IndexedDB, and Storage), but was designed to meet the storage needs of extensions. The following are a few key features:

• All extension contexts, including the extension service worker and content scripts have access to the Storage API.
• The JSON serializable values are stored as object properties.
• The Storage API is asynchronous with bulk read and write operations.
• Even if the user clears the cache and browsing history, the data persists.
• Stored settings persist even when using split incognito.
• Includes an exclusive read-only managed storage area for enterprise policies.

While extensions can use the Storage interface (accessible from window.localStorage) in some contexts (popup and other HTML pages), we don't recommend it for the following reasons:

• Extension service workers can't use the Web Storage API.
• Content scripts share storage with the host page.
• Data saved using the Web Storage API is lost when the user clears their browsing history.

To move data from web storage APIs to extension storage APIs from a service worker:

1. Prepare an offscreen document html page and script file. The script file should contain a conversion routine and an onMessage handler.
2. In the extension service worker, check chrome.storage for your data.
3. If your data isn't found, call createDocument().
4. After the returned Promise resolves, call sendMessage() to start the conversion routine.
5. Inside the offscreen document's onMessage handler, call the conversion routine.

There are also some nuances to how web storage APIs work in extensions. Learn more in the Storage and Cookies article.

The Storage API is divided into the following storage areas:

storage.local

Data is stored locally and cleared when the extension is removed. The storage limit is 10 MB (5 MB in Chrome 113 and earlier), but can be increased by requesting the "unlimitedStorage" permission. We recommend using storage.local to store larger amounts of data. By default, it's exposed to content scripts, but this behavior can be changed by calling chrome.storage.local.setAccessLevel().

storage.managed

Managed storage is read-only storage for policy installed extensions and managed by system administrators using a developer-defined schema and enterprise policies. Policies are analogous to options but are configured by a system administrator instead of the user, allowing the extension to be preconfigured for all users of an organization. For information on policies, see Documentation for Administrators. To learn more about the managed storage area, see Manifest for storage areas.

storage.session

Holds data in memory while an extension is loaded. The storage is cleared if the extension is disabled, reloaded or updated and when the browser restarts. By default, it's not exposed to content scripts, but this behavior can be changed by calling chrome.storage.session.setAccessLevel(). The storage limit is 10 MB (1 MB in Chrome 111 and earlier). Thestorage.session interface is one of several we recommend for service workers.

storage.sync

If syncing is enabled, the data is synced to any Chrome browser that the user is logged into. If disabled, it behaves like storage.local. Chrome stores the data locally when the browser is offline and resumes syncing when it's back online. The quota limitation is approximately 100 KB, 8 KB per item. We recommend using storage.sync to preserve user settings across synced browsers. If you're working with sensitive user data, instead use storage.session. By default, storage.sync is exposed to content scripts, but this behavior can be changed by calling chrome.storage.sync.setAccessLevel().

The Storage API has the following usage limitations:

• Storing data often comes with performance costs, and the API includes storage quotas. We recommend being careful about what data you store so that you don't lose the ability to store data.
• Storage can take time to complete. Make sure to structure your code to account for that time.

For details on storage area limitations and what happens when they're exceeded, see the quota information for sync, local, and session.

The following sections demonstrate common use cases for the Storage API.

To track changes made to storage, add a listener to its onChanged event. When anything changes in storage, that event fires. The sample code listens for these changes:

background.js:

chrome.storage.onChanged.addListener((changes, namespace) => {
  for (let [key, { oldValue, newValue }] of Object.entries(changes)) {
    console.log(
      `Storage key "${key}" in namespace "${namespace}" changed.`,
      `Old value was "${oldValue}", new value is "${newValue}".`
    );
  }
});

We can take this idea even further. In this example, we have an options page that allows the user to toggle a "debug mode" (implementation not shown here). The options page immediately saves the new settings to storage.sync, and the service worker uses storage.onChanged to apply the setting as soon as possible.

options.html:

<!-- type="module" allows you to use top level await -->
<script defer src="options.js" type="module"></script>
<form id="optionsForm">
  <label for="debug">
    <input type="checkbox" name="debug" id="debug">
    Enable debug mode
  </label>
</form>

options.js:

// In-page cache of the user's options
const options = {};
const optionsForm = document.getElementById("optionsForm");

// Immediately persist options changes
optionsForm.debug.addEventListener("change", (event) => {
  options.debug = event.target.checked;
  chrome.storage.sync.set({ options });
});

// Initialize the form with the user's option settings
const data = await chrome.storage.sync.get("options");
Object.assign(options, data.options);
optionsForm.debug.checked = Boolean(options.debug);

background.js:

function setDebugMode() { /* ... */ }

// Watch for changes to the user's options & apply them
chrome.storage.onChanged.addListener((changes, area) => {
  if (area === 'sync' && changes.options?.newValue) {
    const debugMode = Boolean(changes.options.newValue.debug);
    console.log('enable debug mode?', debugMode);
    setDebugMode(debugMode);
  }
});

Because service workers don't run all the time, Manifest V3 extensions sometimes need to asynchronously load data from storage before they execute their event handlers. To do this, the following snippet uses an async action.onClicked event handler that waits for the storageCache global to be populated before executing its logic.

background.js:

// Where we will expose all the data we retrieve from storage.sync.
const storageCache = { count: 0 };
// Asynchronously retrieve data from storage.sync, then cache it.
const initStorageCache = chrome.storage.sync.get().then((items) => {
  // Copy the data retrieved from storage into storageCache.
  Object.assign(storageCache, items);
});

chrome.action.onClicked.addListener(async (tab) => {
  try {
    await initStorageCache;
  } catch (e) {
    // Handle error that occurred during storage initialization.
  }

  // Normal action handler logic.
  storageCache.count++;
  storageCache.lastTabId = tab.id;
  chrome.storage.sync.set(storageCache);
});

You can view and edit data stored using the API in DevTools. To learn more, see the View and edit extension storage page in the DevTools documentation.

The following samples demonstrate the local, sync, and session storage areas:

chrome.storage.local.set({ key: value }).then(() => {
  console.log("Value is set");
});

chrome.storage.local.get(["key"]).then((result) => {
  console.log("Value is " + result.key);
});

chrome.storage.sync.set({ key: value }).then(() => {
  console.log("Value is set");
});

chrome.storage.sync.get(["key"]).then((result) => {
  console.log("Value is " + result.key);
});

chrome.storage.session.set({ key: value }).then(() => {
  console.log("Value was set");
});

chrome.storage.session.get(["key"]).then((result) => {
  console.log("Value is " + result.key);
});

To see other demos of the Storage API, explore any of the following samples:

• Global search extension.
• Water alarm extension.

The storage area's access level.

"TRUSTED_CONTEXTS"
Specifies contexts originating from the extension itself.

• onChanged

  Event<functionvoidvoid>

  Fired when one or more items change.

  The onChanged.addListener function looks like:

  (callback: function) => {...}

  • The callback parameter looks like:

    (changes: object) => void

• Removes all items from storage.

  The clear function looks like:

  (callback?: function) => {...}

  • callback

    function optional

    The callback parameter looks like:

    () => void

  • Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

• Gets one or more items from storage.

  The get function looks like:

  (keys?: string | string[] | object, callback?: function) => {...}

  • keys

    string | string[] | object optional

    A single key to get, list of keys to get, or a dictionary specifying default values (see description of the object). An empty list or object will return an empty result object. Pass in null to get the entire contents of storage.

  • callback

    function optional

    The callback parameter looks like:

    (items: object) => void

    • Object with items in their key-value mappings.

  • Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

• Gets the amount of space (in bytes) being used by one or more items.

  The getBytesInUse function looks like:

  (keys?: string | string[], callback?: function) => {...}

  • keys

    string | string[] optional

    A single key or list of keys to get the total usage for. An empty list will return 0. Pass in null to get the total usage of all of storage.

  • callback

    function optional

    The callback parameter looks like:

    (bytesInUse: number) => void

    • Amount of space being used in storage, in bytes.

  • Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

• Gets all keys from storage.

  The getKeys function looks like:

  (callback?: function) => {...}

  • callback

    function optional

    The callback parameter looks like:

    (keys: string[]) => void

    • Array with keys read from storage.

  • returns

    Promise<string[]>

    Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

• Removes one or more items from storage.

  The remove function looks like:

  (keys: string | string[], callback?: function) => {...}

  • A single key or a list of keys for items to remove.

  • callback

    function optional

    The callback parameter looks like:

    () => void

  • Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

• Sets multiple items.

  The set function looks like:

  (items: object, callback?: function) => {...}

  • An object which gives each key/value pair to update storage with. Any other key/value pairs in storage will not be affected.

    Primitive values such as numbers will serialize as expected. Values with a typeof "object" and "function" will typically serialize to {}, with the exception of Array (serializes as expected), Date, and Regex (serialize using their String representation).

  • callback

    function optional

    The callback parameter looks like:

    () => void

  • Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

• Sets the desired access level for the storage area. By default, session storage is restricted to trusted contexts (extension pages and service workers), while local and sync storage allow access from both trusted and untrusted contexts.

  The setAccessLevel function looks like:

  (accessOptions: object, callback?: function) => {...}

  • • The access level of the storage area.

  • callback

    function optional

    The callback parameter looks like:

    () => void

  • Promises are supported in Manifest V3 and later, but callbacks are provided for backward compatibility. You cannot use both on the same function call. The promise resolves with the same type that is passed to the callback.

• The new value of the item, if there is a new value.

• The old value of the item, if there was an old value.

Items in the local storage area are local to each machine.

• The maximum amount (in bytes) of data that can be stored in local storage, as measured by the JSON stringification of every value plus every key's length. This value will be ignored if the extension has the unlimitedStorage permission. Updates that would cause this limit to be exceeded fail immediately and set runtime.lastError when using a callback, or a rejected Promise if using async/await.

Items in the managed storage area are set by an enterprise policy configured by the domain administrator, and are read-only for the extension; trying to modify this namespace results in an error. For information on configuring a policy, see Manifest for storage areas.

Items in the session storage area are stored in-memory and will not be persisted to disk.

• The maximum amount (in bytes) of data that can be stored in memory, as measured by estimating the dynamically allocated memory usage of every value and key. Updates that would cause this limit to be exceeded fail immediately and set runtime.lastError when using a callback, or when a Promise is rejected.

Items in the sync storage area are synced using Chrome Sync.

• The maximum number of items that can be stored in sync storage. Updates that would cause this limit to be exceeded will fail immediately and set runtime.lastError when using a callback, or when a Promise is rejected.

• MAX_SUSTAINED_WRITE_OPERATIONS_PER_MINUTE

  1000000
  

  The storage.sync API no longer has a sustained write operation quota.

• MAX_WRITE_OPERATIONS_PER_HOUR

  1800
  

  The maximum number of set, remove, or clear operations that can be performed each hour. This is 1 every 2 seconds, a lower ceiling than the short term higher writes-per-minute limit.

  Updates that would cause this limit to be exceeded fail immediately and set runtime.lastError when using a callback, or when a Promise is rejected.

• MAX_WRITE_OPERATIONS_PER_MINUTE

  120
  

  The maximum number of set, remove, or clear operations that can be performed each minute. This is 2 per second, providing higher throughput than writes-per-hour over a shorter period of time.

  Updates that would cause this limit to be exceeded fail immediately and set runtime.lastError when using a callback, or when a Promise is rejected.

• The maximum total amount (in bytes) of data that can be stored in sync storage, as measured by the JSON stringification of every value plus every key's length. Updates that would cause this limit to be exceeded fail immediately and set runtime.lastError when using a callback, or when a Promise is rejected.

• QUOTA_BYTES_PER_ITEM

  8192
  

  The maximum size (in bytes) of each individual item in sync storage, as measured by the JSON stringification of its value plus its key length. Updates containing items larger than this limit will fail immediately and set runtime.lastError when using a callback, or when a Promise is rejected.

chrome.storage.onChanged.addListener(
  callback: function,
)

Fired when one or more items change.

• The callback parameter looks like:

  (changes: object, areaName: string) => void

Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.

Last updated 2025-07-11 UTC.

[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-07-11 UTC."],[],[]]

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4