https://www.hostinger.com/tutorials/website/improving-websit...
Progressive JPEGs are somewhat similar, but IIRC didn't gain traction until 2000 or so.
I remember the first ProLiant server we flipped to support SSL had to have an add-in card to accelerate the encryption based on the traffic we handled. It was something like this: https://www.hpe.com/psnow/doc/c04283920.PDF?jumpid=in_pb-psn...
HTML content? In the javascript. Style information? In the javascript. A way to negotiate network loading and resources, document structure? You guessed it. Want the back button to work again? More JavaScript. URLs to be universal? Even more!
Eventually you'll get the page to be almost as functional as it would have been by default had you not used any of it.
Read the mdn and w3c documentation guys, I promise you 99.9% of what you want is in there without reinventing it from base principles. It's not 2010 anymore
It's like a bad cook who is trying to fix a poorly made meal by making more mistakes, covering it in salt and oil, smearing honey over it, and calling it delicious.
Overall, it's really great though. I love the stuff popping up on Neocities.