WindowSharedStorage: worklet property

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The worklet read-only property of the WindowSharedStorage interface contains the SharedStorageWorklet instance representing the shared storage worklet for the current origin.

SharedStorageWorklet contains the addModule() method, which is used to add a module to the shared storage worklet.



// Randomly assigns a user to a group 0 or 1
function getExperimentGroup() {
  return Math.round(Math.random());

async function injectContent() {
  // Add the module to the shared storage worklet
  await window.sharedStorage.worklet.addModule("ab-testing-worklet.js");

  // Assign user to a random group (0 or 1) and store it in shared storage
  window.sharedStorage.set("ab-testing-group", getExperimentGroup(), {
    ignoreIfPresent: true,

  // Run the URL selection operation
  const fencedFrameConfig = await window.sharedStorage.selectURL(
      { url: `https://your-server.example/content/default-content.html` },
      { url: `https://your-server.example/content/experiment-content-a.html` },
      resolveToConfig: true,

  // Render the chosen URL into a fenced frame
  document.getElementById("content-slot").config = fencedFrameConfig;


See the Shared Storage API landing page for a walkthrough of this example and for links to other examples.


Shared Storage API
# dom-windowsharedstorage-worklet

Browser compatibility

BCD tables only load in the browser

See also