Continuations are a very old concept, and you'll be finding many programming languages have support before that. For example, Scheme had continuations (call/cc) since 1975, and I'm sure there must have been implementations before that.

I remember them too. I had to dig a little to find the links I remember from the past.

http://web.archive.org/web/20190127111220/https://wiki.apach...

From the Rhino Google group, it looks like some people are still using continuations in Rhino:

https://groups.google.com/forum/#!topic/mozilla-rhino/Gfo-dO...

https://github.com/szegedi/spring-web-jsflow

They were great. You could serialise them, store them in a database and then deserialise them some time later and keep going. Cheap workflow engine.