The PCjs Project is a fantastic open-source library of in-browser, JavaScript-based emulators, but its primary focus is on classic, much older hardware from the 1970s and 1980s.
An exceptionally smooth browser-based recreation of the Windows XP desktop environment. It features functional classic windows, the classic start menu, and even basic apps. Pcjs Windows Xp
You click through the Control Panel. You open the Display Properties. You watch the 3D Pipes screensaver render endlessly. And you realize—you are not troubleshooting. You are visiting a graveyard. And the grave is your own past self. PCjs does not currently support or emulate Windows XP
PCjs Windows XP: The Ultimate Guide to Browser-Based Emulation It features functional classic windows, the classic start
: A nearly complete experience showing the introduction of the Start menu and Taskbar. Recommended Alternatives for Windows XP Emulation
PCjs is a highly specialized, web-based x86 emulator project that brings classic computing history directly into your modern browser. While it is famous for its pixel-perfect recreations of early IBM PCs and Windows 1.0 through 95, its support for represents the "bleeding edge" of browser-based emulation. The Experience: Retro Computing in a Tab