All desktop browsers (I think/hope) support bookmarklets -- bookmarks that contain JavaScript code which is run when you select them. This bookmarklet makes it easier to follow users or interact with toots from other Mastodon instances by passing their URLs back to your home instance, where you can then follow/interact with them normally.
The bookmarklet:
javascript:var host="mastodon.social";if(document.location.hostname==host){alert("Already on your own instance!")}else{document.location=("https://"+host+"/authorize_interaction?uri="+encodeURIComponent(document.location))}