I built an actual shipping product that used this approach over 25 years ago. The server would have the state of every session, that would be serialized to xml, and then xslt templates would be used to render html. Idea was that this would allow customers to customize the visual appearance of the webpages, but xslt was too difficult. Not a success.
I did something like this at an employer a while ago as well. Taking it a step further, we wanted to be able to dynamically build the templates that the browser would then use for building the HTML. Senior dev felt the best way would be to have a "master" xslt that would then generate the xslt for the browser. I ended up building the initial implementation and it was a bit of a mind bender. Fun, but not developer friendly for sure .
