The earliest work of which I am aware is documented in the excellent book Beyond Webcams: An Introduction to Online Robots. Nov 2001. Eds. Ken Goldberg and Roland Siegwart. MIT Press. ISBN: 9780262072250. Beyond Webcams
It describes remote access to lab robots from around the years 1995, 1997, so some screenshots show the Mosaic Web browser, and some of the authors discuss using Java applets and clever tricks to make user’s Web pages refresh (because modern JavaScript did not exist yet).