We did have them 25 years ago. https://learn.microsoft.com/en-us/previous-versions/windows/internet-explorer/ie-developer/platform-apis/ms532853(v=vs.85) https

We did have them 25 years ago. https://learn.microsoft.com/en-us/previous-versions/windows/internet-explorer/ie-developer/platform-apis/ms532853(v=vs.85) https://learn.microsoft.com/en-us/previous-versions/windows/... The documentation there may not make it clear, but you could do things like navigate from one page to the next, and fade in the new page, from a normal full page reload, with no intermediate flash of unstyled anything. It was part of the attempt to lock the web into DirectX and even Microsoft themselves deprecated this a long time ago. But it definitely worked. I remember playing with it. IE4 though IE6-ish had a lot of weird stuff in it to try to drive lock in.