GameBoy Online is a Game Boy and GameBoy Color emulator written in Javascript. It strives to be efficient and try to have a perfect compatibility. Currently the execution speed is not optimal even on browsers. For example on Chrome, which is nevertheless deemed to run Javascript faster on a PC running Windows 7 64-bit version with a double heart 2 CPUs at 2.2 GHz, games run at normal speed but almost skipping some frames.

The sound production is still experimental and rather poor quality. The video portion is by HTML5 or by creating images with BMP string URI. State backups are implemented using the object window.localStorage and are serialized / deserialized JSON. Ditto for backup SRAM.



GameBoy Online Changelog:
- Reverting a change to allow the ROM to set the exact MBC RAM size, reverting back to automatic sizing based on the set MBC cartridge type instead.
- oops
- Audio channel 1 accurate shadow register implementation.
- 7-bit LSFR accuracy update (For EXACT channel 4 7-bit LSFR generation (Before we just re-used 15-bit LSFR results, which pretty much was the same thing.)).

Play Online: GameBoy Online (2011/09/04)
Source: Here