Compatibility

Discouraged Practises

• document.cookie is known not to work on desktop and iOS—use localStorage instead
• unload, beforeunload and pagehide events are known not to work on iOS and are flaky on other systems (also partly discouraged by mozilla)—use visibilitychange instead
• <title> and document.title is ignored by Webxdc; use the name property from manifest.toml instead
• the latest JavaScript features may not work on all webviews, you may want to transpile your code down to an older js version e.g. with https://babeljs.io
• <a href="https://example.org/foo"> and other external links are blocked by definition; instead, embed content or use mailto: link to offer a way for contact
• <a href="data: or otherwise internal"> is not guaranteed to open a download dialog; instead, use sendToChat() to export files.
• features that require user permissions or are enabled through the Permissions Policy may not work, Geolocation, Camera, Microphone etc.
• window.open(), alert(), prompt(), confirm(), is known to not work on some implementations

Transpile Newer JavaScript With Babel.js

Older devices might not have the newest javascript features/syntax in their webview, you may want to transpile your code down to an older JavaScript version eg. with Babel.

Targets:

• Desktop (electron -> is chrome 91)
• iOS (iOS 11 -> webkit 604.1.38)
• android (android 5 -> the webview system component can be updated by the user: https://play.google.com/store/apps/details?id=com.google.android.webview)

If you want to use a newer API make sure to check on https://caniuse.com. If you just want to use newer JavaScript syntax, babel.js is the right tool for you - it translates new JS into older JS, that can be interpreted.