title: Get notified when indexedDB entry gets changed in other tab
body: <p>If a user opens multiple instances of a web app in multiple tabs, any instance can be notified of changes to <code>localStorage</code> that any other instance makes by registering a <code>storage</code> event listener. A tab receiving such a notification might then react and e.g. update the UI according to the changes.</p>
  
  <p>Indexed DB doesn't seem to offer a similarly convenient mechanism for such notifications. Would one have to use <code>localStorage</code> to "send" a notification to other tabs whenever making changes to Indexed DB? The only other alternative might be polling, which is clearly inferior to <code>storage</code> events.</p>