Fizzygum
Try a new web framework that handles complex things, easily
...Built with JavaScript and WebAssembly, it features a windowing system, file system abstraction, terminal emulator, and GUI apps—all running inside the browser. Fizzygum is designed as a playground for experimenting with web-native system design and is ideal for educational demos, rapid UI prototyping, and understanding OS principles in a high-level, accessible environment.