GitHub - alganet/neutrino: Single-file, polyglot cross-platform webview launcher

2 min read Original article ↗

neutrino is a single-file, cross-platform launcher that opens a native desktop window containing a web page.

It uses one polyglot entrypoint (webview.cmd) that can run on:

  • Windows (cmd + JScript.NET + WinForms/WebView2)
  • Linux (sh + gjs/GTK WebKit, with Qt QML fallback)
  • macOS (sh + osascript/JXA + Cocoa WebKit)

Default page:

  • https://alganet.github.io/ (for testing purposes, can be changed)

How it works

webview.cmd is intentionally written as a multi-runtime script.

  • On Windows, it compiles its embedded JScript.NET section with jsc.exe to an executable and launches it.
  • On Linux/macOS, it behaves like a shell script that invokes the best available runtime.
  • The same file also embeds an HTML payload used by the runtime-specific logic.

The script automatically tries available runtimes in this order on Unix-like systems:

  1. gjs
  2. Qt QML runtime (qml6, qmlscene6, qmlscene-qt6, qml, qmlscene)
  3. osascript (macOS)

The QML runtime integration is currently experimental and under development.

Requirements

Windows

  • .NET Framework with jsc.exe (v4.x) - Available on modern Windows machines by default.
  • WebView2 runtime installed - Downloaded with progress bar upon first run.

Linux

  • Preferred: gjs + GTK/WebKit2 bindings - Available on all major GNOME distros.
  • Fallback: Qt runtime with QtWebEngine - Available on all major KDE distros.

macOS

  • osascript with JavaScript support (JXA) - Available on macos by default.

Run

From the project root:

Linux / macOS

chmod +x webview.cmd
./webview.cmd

Windows

Configuration

Page URL

  • Default URL is embedded in the script as https://alganet.github.io/.

Script path propagation

  • The launcher exports NEUTRINO_SCRIPT_PATH so child runtimes can resolve the source script consistently.

Output layout (Windows)

When executed as webview.cmd, Windows creates/uses a sibling directory named after the script base name:

./webview.cmd
./webview/
  webview.exe
  webview.exe.manifest
  ...runtime assets...

Repository

  • webview.cmd — polyglot entrypoint and runtime implementation
  • LICENSE — ISC license

License

ISC. See LICENSE.