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Window.sessionStorage

The read-only sessionStorage property accesses as session Storage object for the current origin. sessionStorage is similar to localStorage; the difference is that while data in localStorage doesn't expire, data in sessionStorage is cleared when the page session ends.

  • Whenever a document is loaded in a particular tab in the browser, a unique page session gets created and assigned to that particular tab. That page session is valid only for that particular tab.
  • A page session lasts as long as the tab or the browser is open and survives over page reloads and restores.
  • Opening a page in a new tab or window creates a new session with the value of the top-level browsing context, which differs from how session cookies work.
  • Opening multiple tabs/windows with the same URL creates sessionStorage for each tab/window.
  • Closing a tab/widows ends the session and clears objects in sessionStorage

Example

Basic usage

// Save data to sessionStorage
sessionStorage.setItem('key', 'value');

// Get saved data from sessionStorage
let data = sessionStorage.getItem('key');

// Remove saved data from sessionStorage
sessionStorage.removeItem('key');

// Remove all saved data from sessionStorage
sessionStorage.clear();

Save text between refreshes

// Get the text field that we're going to track
let 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);
});

Reference