Shared Storage API Demo - Online Cross‑Site Data

// Write data (requires user interaction context)
await window.sharedStorage.set('key', 'value');

// Read data
const val = await window.sharedStorage.get('key');
console.log(val); // 'value'

// Delete
await window.sharedStorage.delete('key');

// Clear all
await window.sharedStorage.clear();

// worklet.js
class SelectUrlOp {
  async run(urls, data) {
    const group = await this.sharedStorage.get('exp-group');
    const idx = group === 'b' ? 1 : 0;
    return idx; // 0-based index into urls array
  }
}
register('select-url', SelectUrlOp);

// Main thread
const worklet = await window.sharedStorage.createWorklet();
await worklet.addModule('worklet.js');
const selected = await worklet.selectURL(
  'select-url',
  ['/page-a', '/page-b'],
  { data: { campaign: 'spring' } }
);

// HTTP Response Header
Permissions-Policy: shared-storage=(self "https://trusted.example")

// Iframe allow attribute
<iframe allow="shared-storage" src="..."></iframe>

// Meta tag (not all browsers)
<meta http-equiv="Permissions-Policy"
      content="shared-storage=(self)">