Share to Mastodon Link

This is used on ChristianHeilmann.com to share the current post to Mastodon.

It is a simple link that opens a popup window with the Mastodon share dialog.

The main issue is that I can't know your mastodon instance. So the first time a user clicks the link, I ask for the instance and store it subsequently in local storage.

Once set, you also get an edit link next to the share button to edit your instance in case you made a mistake.