Can you use Win32 GUI in a browser plugin?

Of course it would mean you're plugin is not cross-platform but let's focus on the technical side...

Is a browser plugin (like done in NPAPI) restricted in what it can do? Or do you get fairly free reig开发者_StackOverflow中文版n to access the PC and the render-window you're given? For instance can you create Win32/MFC controls in your browser this way?

A side question - is your browser plugin conceptually akin to a .DLL, which is therefore just arbitrary compiled code implementing a specific interface for browser control/communication?

There are 2 types of NPAPI plugins: windowed and windowless plugins. Both of them has some advantages and disadvantages (see this link). When you deal with windowed plugin on Win32 you get HWND of browser plugin window and you can work with it like with any window in OS.