gbajs2 is a Game Boy Advance emulator written in Javascript from scratch using HTML5 technologies like Canvas and Web Audio. It is freely licensed and works in any modern browser without plugins.
Under the homebrew heading, there are multiple custom open source games - even something as simple as a flappy bird clone being loaded/available by default would make it much easier to check out your emulator (especially its performance compared to WASM projects)
https://github.com/gbdev/awesome-gbdev
Under the homebrew heading, there are multiple custom open source games - even something as simple as a flappy bird clone being loaded/available by default would make it much easier to check out your emulator (especially its performance compared to WASM projects)