EM-DOSBox
EM-DOSBox is a free DOSBox version compiled with Emscripten to run DOS games and other DOS programs in a web browser.
What EM-DOSBox is
EM-DOSBox is a free DOSBox version compiled with Emscripten to run DOS games and other DOS programs in a web browser. The project reports that most games run successfully, although some programs may encounter paging exceptions. Asyncify is enabled by default, supporting more DOSBox features and interactive file loading with a stated small performance cost. An Emscripten build creates dosbox.js, dosbox.wasm when WebAssembly is enabled, and a simple dosbox.html interface. Packager tools can create pages that load DOS files into the browser file system, pass command-line arguments, and launch a selected game or program. A packaged dosbox.conf can adjust emulator speed, audio, and graphics. Listed disk formats include ISO, CUE/BIN, CUE/IMG, floppy images, and hard-drive images; gamepad and audio CD support are also listed. Pages should be served through a web server because browsers commonly restrict access from file URLs. Building requires recent stable Emscripten, GNU Autotools, and a Unix-like environment; Windows builds are unsupported. Packager tools require Python 3. Saved games are held in memory and disappear when the page closes.
Good
- Runs DOS programs in a web browser
- Asyncify enables interactive file loading
- Packagers launch chosen games with arguments
- Configurable speed, audio, and graphics
- Supports gamepads and audio CDs
Watch out
- Some programs may encounter paging exceptions
- Saved games disappear when the page closes
- Windows builds are unsupported
- Pages need serving through a web server
Who it suits
EM-DOSBox suits people who want to run DOS software in browsers and package selected games or programs for web use. It also fits developers comfortable with Emscripten and Unix-like build tools.
Verdict
EM-DOSBox brings DOSBox software into browser pages with packaging and configuration tools. Its in-memory saves and Unix-oriented build requirements matter when planning regular use.
The facts
Each one read from EM-DOSBox's own pages, with the date it was checked.
What it does
- Asyncify
- Asyncify is enabled by default to make more DOSBox features work, with what the project describes as a very small performance penalty.checked 4 Oct 2026
- Build limitation
- Compiling in Windows is not supported because the build process requires a Unix-like environment and GNU Autotools.checked 5 Oct 2026
- Build output
- The build creates dosbox.js and, when WebAssembly is enabled, dosbox.wasm, along with a simple HTML interface.checked 5 Oct 2026
- Compatibility
- The project says most games run successfully in web browsers, though a few programs can have problems due to paging exceptions.checked 5 Oct 2026
- Configuration
- A dosbox.conf file can be included in a package to change emulator speed, audio, or graphics settings.checked 4 Oct 2026
- Creator credit
- The README credits Boris Gjenero with getting the Emscripten port working, fixing issues, and improving performance.checked 4 Oct 2026
- Credits
- The project credits Boris Gjenero with getting DOSBox working through Emscripten and improving its performance for browser use.checked 5 Oct 2026
- Customization
- A packaged DOSBox configuration file can change speed, audio, or graphics settings.checked 5 Oct 2026
- Dependencies
- Building requires a recent stable Emscripten version, and the packager tools require Python 3.checked 5 Oct 2026
- License
- The repository identifies DOSBox as distributed under the GNU General Public License and links to its GPL-2.0 license file.checked 5 Oct 2026
- Loading programs
- The included packager tools can create web pages that load DOS files into the Emscripten file system and pass command-line arguments to DOSBox.checked 4 Oct 2026
- Packaging
- The included packager tools can create web pages that load DOS files and launch a specified game or program.checked 5 Oct 2026
- Purpose
- EM-DOSBox is a DOSBox version that can be compiled with Emscripten to run DOS games and programs in a web browser.checked 5 Oct 2026
- Save-file limitation
- Saved games go into an in-memory Emscripten file system by default and are lost when the web page is closed.checked 4 Oct 2026
- Save files
- Game saves go into an in-memory Emscripten file system by default and are lost when the web page is closed.checked 5 Oct 2026
- Status
- The project says it runs most games successfully in web browsers, though some programs can encounter paging exceptions.checked 4 Oct 2026
Where it runs
- Browser features
- With Asyncify enabled, users can interactively load files into DOSBox.checked 5 Oct 2026
- Browser serving
- The README says to serve the page over a web server because most browsers prevent access to required files through file:// URLs.checked 5 Oct 2026
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