• The impact of iOS 16 Lockdown mode in Safari

    From Jolly Roger@21:1/5 to All on Sat Jul 23 00:08:16 2022
    XPost: misc.phone.mobile.iphone

    Alexis Lours did some testing and published details about the effects of Apple's upcoming Lockdown Mode on Safari - cool stuff.

    The impact of iOS 16 Lockdown mode in Safari <https://blog.alexi.sh/posts/2022/07/lockdown-jsc/>
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    A look at how the new iOS lockdown mode affects web performances and features.

    July 22, 2022 · 5 min · 966 words · Alexis LOURS

    The iOS 16 beta 3 introduced a new privacy feature: Lockdown Mode. The
    idea is to disable some features in iOS to reduce the possibility of
    privacy related attacks.

    Apple also gives a rough list of the features disabled in Lockdown,
    including one which caught my eye:

    Web browsing: Certain complex web technologies, like just-in-time (JIT) JavaScript compilation, are disabled unless the user excludes a trusted
    site from Lockdown Mode.[1]

    The first thing I thought was that disabling JavaScript JIT compilation
    in JavaScriptCore would cause a major drop in performance, given the
    amount of JavaScript used in webpages. I wanted to test how big this
    impact would be.

    The second was figuring out what’s included in “Certain complex web technologies," since Apple did not provide an explanation.

    Disabled features

    Through manual testing and Modernizr fe