Show availability of site name or username automatically next to form field

[simonbaird]

Could show if the name is valid and available without requiring a form submit. It's a common UI element - there might be a useful bootstrap or jquery plugin for it already.

Could be a "Check availability" button, or it could happen automatically after a few seconds once the user stops typing.

[simonbaird]

I was playing with htmx.org for doing this kind of thing. Seems promising.