Defaults Flags

Some Aqua WebKit settings can be changed via defaults write commands on the command line.

Shared Cookies

By default, on Mavericks, all apps which use WebKit use a shared set of cookies, unless the app is sandboxed. To disable this for an app, use:

defaults write <bundle id> AquaWebKitUsesSystemCookieJar -bool false

Unlike other options, this does not support -g to write to the global domain, it must be set per app.

JSC Options

Want to disable JIT, or WASM? You can use:

defaults write <bundle id> AquaWebKitJSCOptions "useJIT=false" defaults write <bundle id> AquaWebKitJSCOptions "useWasm=false"

Other keys you could (probably don't want to) use are useGenerationalGC=false, useConcurrentGC=false, useLLIntICs=false, useZombieMode=true, allowDoubleShape=false, and alwaysHaveABadTime=true.

Play Media Inline

To make direct links to media files play inside WebKit instead of downloading: defaults write <bundle id> AquaWebKitPlayMediaFilesInline true

Fullscreen style

To make full screen elements open in the same space instead of a different one, use:

defaults write <bundle id> AquaWebKitLionStyleFullScreen -bool false

This does not apply to Safari's Enter Full Screen, only e.g. full screening a video.