What is macintosh.js?

macintosh.js is a desktop application that runs Mac OS 8 inside a modern-day window on your current computer. It emulates a 1991 Macintosh Quadra 900, a specific model of old Apple computer that used a Motorola processor. The entire emulator is built with JavaScript and packaged as a standalone app using Electron, which is a framework that lets web technologies run as desktop applications. The project description includes the words "I'm sorry" because shipping a full operating system emulator as a JavaScript app is exactly as questionable as it sounds. It runs on Windows, macOS, and Linux, with downloadable installers for 32-bit and 64-bit versions of each. The app comes preloaded with content from a 1997 MacWorld Demo CD, so you get classic games like Oregon Trail, Duke Nukem 3D, and Civilization II out of the box. Several commercial applications from that era are also pre-installed, including early versions of Photoshop, Premiere, and Illustrator. You can transfer files into and out of the virtual machine, and there is a Help button in the running app that explains how. A virtual Ethernet card is present, which lets two copies of macintosh.js on the same local network communicate with each other using the AppleTalk protocol that old Macs used. Full internet access would require additional software that is not bundled, and even then the 1997-era browsers installed on the disk image would not work with most of today's websites. The README is candid that this is a toy project made for nostalgia and curiosity, not a practical tool for any serious use. The underlying emulation work comes from two other developers, Christian Bauer and James Friend, whose prior work made this possible. The project is offered for educational purposes and is not affiliated with Apple.