The sessionStorage
property allows you to access a session Storage
object for the current origin. sessionStorage is similar to Window.localStorage
, the only difference is while data stored in localStorage has no expiration set, data stored in sessionStorage gets cleared when the page session ends. A page session lasts for as long as the browser is open and survives over page reloads and restores. Opening a page in a new tab or window will cause a new session to be initiated, which differs from how session cookies work.
It should be noted that data stored in either sessionStorage or localStorage is specific to the protocol of the page.
Syntax
// Save data to sessionStorage sessionStorage.setItem('key', 'value'); // Get saved data from sessionStorage var data = sessionStorage.getItem('key'); // Remove saved data from sessionStorage sessionStorage.removeItem('key'); // Remove all saved data from sessionStorage sessionStorage.clear();
Value
A Storage
object.
Example
The following snippet accesses the current domain's session Storage
object and adds a data item to it using Storage.setItem()
.
sessionStorage.setItem('myCat', 'Tom');
The following example autosaves the contents of a text field, and if the browser is accidentally refreshed, restores the text field content so that no writing is lost.
// Get the text field that we're going to track var field = document.getElementById("field"); // See if we have an autosave value // (this will only happen if the page is accidentally refreshed) if (sessionStorage.getItem("autosave")) { // Restore the contents of the text field field.value = sessionStorage.getItem("autosave"); } // Listen for changes in the text field field.addEventListener("change", function() { // And save the results into the session storage object sessionStorage.setItem("autosave", field.value); });
Note: Please refer to the Using the Web Storage API article for a full example.
Specifications
Specification | Status | Comment |
---|---|---|
WHATWG HTML Living Standard The definition of 'sessionStorage' 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 | (Yes) | 2 | 8 | 10.50 | 4 |
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.