For those of you too young to remember, all the early web browsers supported telnet: URLs, usually launching an external telnet client.

At least Firefox still does. Actually it supports any foo:// protocol if you're willing to configure an external program to handle it :)

Edit: instructions here http://kb.mozillazine.org/Register_protocol

I have a vague memory of using a telnet URL in a browser to play a text-only MUD back in the 90's. Was exotic compared to the default way of doing it in a terminal shell session.

I'd imagine the address bar itself would accept the ssh:// protocol.