That's pretty hard to do. The flash projector is a windows program, it's not built to work in a browser.
Looking online for "run windows app in browser" brings up paid services that run your app on a server, and then you can interact with it from the browser
I don't think that's worth it. But if you're interested take a look at this thing https://www.rollapp.com/apps
It doesn't have flash, but gives you an idea about how it could work (you'll have to make a throwaway account to run an app)
There *is* another way...>Boxedwine is an emulator that runs Windows applications. It achieves this by running an unmodified 32-bit version of Wine, and emulating the Linux kernel and CPU.
In other words your browser emulates the operative system linux which runs wine (a program which attempts to make it possible to run windows apps on linux by sort of "emulating" it) to run flash projector. Needless to say performance is not good, it takes a lot to load, lags as fuck, also boxedwine seems to only work with very old windows programs. However the projector seems to work alright on wine (on a real linux)>https://appdb.winehq.org/objectManager.php?sClass=application&iId=15096
In a few years maybe.