Maybe my memory is fuzzy, but I don't remember Flash being used for apps. It got used for video playing and games mostly, as well as unnecessary animation on restaurant/hotel websites. The occasional enterprise app used it, but generally they were ActiveX.

What we had was server-side frameworks. Generated HTML, click a link that does a GET or POST. That's how my webmail at University worked, that's how the control panel for my web hosting worked etc.

I think my first exposure to proper clientside UI was GMail (lunched 2004, I think I signed up ~2006).

>Maybe my memory is fuzzy, but I don't remember Flash being used for apps

Flash was used for apps; I remember one webmail provider which had built their frontend in Flash (can't remember the name sadly), and there various enterprise apps that were deployed with Adobe Flex (I remember Paychex being one of them).

Adobe really wanted it to be used for serious stuff. There was AIR, a Flash desktop runtime. They started integrating Flash into their tools, I recall a few Illustrator palettes that would make my computer’s fans come on just by opening them because they would make the Flash runtime wake up and start busy-waiting for input on them.

They had the same vision for it that Sun had for Java, with the same flaws that would become apparent when that vision was finally manifested in Electron: write once, run anywhere, and be hideously inefficient compared to native code.

That's what I remember too - but what's the difference between an app and a game? Usually your score would be sent back to the server too.

A managed switch we use somewhere for something uses flash to display port status (I think?). I guess that part doesn't work anymore...

Up through 2008 we made very heavy use of posts in web apps where I worked, js was more of an accelerant for things like autocomplete and client side validation. Amazon retail was still building mostly post based experiences when they were doing the universal detail page project in 2015.

I never used flash seriously from 1996-2015 when I switched to an electron front end and then mostly to backend work.