Q:

Service workers fetch event listener: what does it catch? 

I have an issue with catching fetch events from a service worker. 
In a page at https://localhost/subdir/page.php I register the service worker with:
navigator.serviceWorker.register('https://localhost/subdir/sw.js', {scope: './'}).then( ... );

I then register the Fetch event listener with:
this.addEventListener('fetch', function(event) { ... });

In the same page at https://localhost/subdir/page.php I then have four different kinds of links:
<a href="https://localhost/subdir/page2.php">link1</a><br />
<a href="http://localhost/subdir/page2.php">link2</a><br />
<a href="https://otherhost">link3</a><br />
<a href="http://otherhost">link4</a><br />

I noticed that the service worker only catches the fetch event from link1, leaving the other three unnoticed. 
Every test I made seems to suggest that the service worker gets notified only for requests going to its own origin. 
Can anyone confirm this? 
Any known workaround? 
Thanks in advance

A:

Yes, that's how it's supposed to work for navigations.  You shouldn't be able to intercept the user going to a different site. ( You do get access to all subresource requests of the document, regardless of origin.)